Microstutter in latest-gen cards - examples included

Not 100% sure where to post this, so I'm putting it here because I'd like to see some results from ATI users as well.

Microstutter, for those that don't know, is the irregular output of frames - usually as a result of multi-GPU setups operating in AFR mode. Since the human eye notices the gap between frames as a measure of smoothness, rather than the raw number of frames spit out, then a game with irregular frame output will not look as smooth as one with uniform output.

It stands to reason, for example, that a game outputting two frames 0.1ms apart, with a 49.9ms gap until the next frame, would look like it was running at 20fps, even though the framerate counter would read 40fps.


Aaaanyway. A while back I wrote a little program to quantify microstutter from FRAPS benchmarks. You can download it here. Basically it looks at the frame-by-frame variation from the local frametime, as a percentage of the average frametime (more details in the readme). From this you can gain a "microstutter index", which you can think of as a "percentage microstutter", 100% being the scenario I described above. It also shows an "effective framerate", which is a measure of smoothness with microstutter taken into account. An equivalent framerate if there was no microstutter.


Okay, now onto some examples. First I'll show you a snapshot of 35 consecutive frametimes I took from the middle of a crysis benchmark, using my GTX480 SLI setup. Not all the scene was as bad as this, but it gives you an idea of the problem:

http://img227.imageshack.us/img227/6...livssingle.png


In terms of the microstutter index, the runs that generated the plots above, had the following results.

Single GPU (2560*1600, 4xAA):

http://img843.imageshack.us/img843/9...rysis25604.png



SLI (2560*1600, 4xAA):

http://img810.imageshack.us/img810/9...rysis25604.png


This isn't as bad as with my old 4870x2, but it certainly shows that microstutter is still with us.

Now, it's important to note that as the game becomes less and less GPU limited, the microstutter effect reduces significantly. For example, the above benchmark had the GPUs running at near-100% load. At 1920*1200, 8xQAA, the GPUs are in the region 85-95% load for the most part. Here the microstutter index drops significantly:


http://img534.imageshack.us/img534/5...rysis19208.png


Okay, well that's my findings. What I'd love to see is some results from ATI users, with multi-GPU setups. I'd like to compare the two technologies and see how they compare. Please post any results you generate, but please make sure you're really at, or close to, 100% GPU load, otherwise you will see an artificially low microstutter index. Afterburner is a good way to check this.

My hope is that maybe, just maybe, if we can generate more awareness of this problem we can get ATI / nvidia driver teams to pay attention and do something about it. A 5% performance drop (say) would be a small price to pay for regular frame output. Of course, this will not happen until review sites start taking note of microstutter when reviewing cards!

Here, i did some crysis benchmarks with 4890 crossfire:

http://paulyd.co.uk/oz/crysisbench.jpg

0xAA run:
http://paulyd.co.uk/oz/microstutter_noaa.jpg

8xAA run:
http://paulyd.co.uk/oz/microstutter_8aa.jpg


These were done with an i7 860 (HT off) at 4.0GHz (200x20), RAM at 2000 CL7 and 4890 crossfire at 900 core 1100 memory.

Thanks...

Not too bad to be honest :) I generally found worse performance with my old 4870x2.

No problem :toast:

Here's another one, Dirt 2 this time:

http://paulyd.co.uk/oz/dirt2microstutter.jpg


FPS in the benchmark was 116. 1680x1050, maxed, 4xAA. Funny enough i found i need to enable vsync to get the smoothness i desire, otherwise i can feel the microstutter. So i would think anything over 15-20% the mircostutter is quite noticeable, if this program is accurate :)

Quote:

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Originally Posted by Arseface

Now, it's important to note that as the game becomes less and less GPU limited

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You meant less CPU dependent, GPU bound/limited to be precise.
High resolution, high game details & AA/AF = nearly 100% GPU limited ( 99.5% of the stress is put on the VGA/s )

Quote:

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Originally Posted by BenchZowner

You meant less CPU dependent, GPU bound/limited to be precise.
High resolution, high game details & AA/AF = nearly 100% GPU limited ( 99.5% of the stress is put on the VGA/s )

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Well whatever you choose to call it :p

The point is, that as the effective load on the GPUs is reduced (i.e. as their percentage utilisation over the benchmark drops), the effect of microstutter is rapidly reduced. This makes sense to a certain degree; if the GPUs are waiting for information from the CPU, then they will start to sync their output with the output from the CPU. The CPU will always be expected to compete its frame-by-frame workload in regular intervals (or at least in smoothly varying intervals).

In the case I showed above, with an overclocked GTX480 SLI setup, even crysis at 1920*1200 with 8xAA is not completely GPU bound. The GPU utilisation is around 85-95%, and this helps reduce the microstutter index significantly (compared to the 2560 test, where GPU utilisation is near-100%). I will test even lower resolutions tonight, for a true CPU-bound scenario. I expect very little microstutter then (but who knows!).

My point was that dropping from ~100% GPU load down to even ~90% load makes a big difference to microstutter.

What are you using to measure the VGA/s utilization ?
Not nVperf kit I assume.
Because at 1920x1200 8xAA the VGA utilization should be 100% unless your CPU is clocked under 3.8GHz

Quote:

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Originally Posted by BenchZowner

What are you using to measure the VGA/s utilization ?
Not nVperf kit I assume.
Because at 1920x1200 8xAA the VGA utilization should be 100% unless your CPU is clocked under 3.8GHz

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I'm using afterburner.

My CPU is an i7-930 clocked at 4.2Ghz. I imagine that if I reduce the CPU clock by a few hundred Mhz I will see 100% GPU utilisation once again (as I do with the 2560 tests), and with it a higher microstutter index. Another thing I could test...

If you're running SLi, then bumping your maximum pre rendered frames from the default 3 to 5 can really help to steady your framerate and make games run smoother; especially in demanding games like Crysis.

Mine is always set to 5, and you and I seem to have a very similar rig, ie 30 inch monitor and GTX 480 SLi.

Quote:

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Originally Posted by Carfax

If you're running SLi, then bumping your maximum pre rendered frames from the default 3 to 5 can really help to steady your framerate and make games run smoother; especially in demanding games like Crysis.

Mine is always set to 5, and you and I seem to have a very similar rig, ie 30 inch monitor and GTX 480 SLi.

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Thanks! I'll give this a try in a couple of hours, when I get back from work :) Sounds like it might be a bit of a trade-off between frame rate regularity and input-lag though. I suppose that rendering more frames ahead will increase the lead time between user actions appearing on-screen?


Unfortunately I'm on a 1920*1200 screen right now :( My 30"-er died around six weeks ago under warranty, and I'm trying to get in contact with the manufacturer to get a replacement, but they are trying their best to ignore me (seems to be heading towards legal action). But anyway - this is a different story!

The crysis benchmark is odd in that it allows you to run at higher resolutions that your monitor is capable of, and downscale to native res. Makes the green in-bench statistics hard to read, but good enough for simulating 2560 30" performance (and more importantly, maxing out the GPUs).

can you make a graph with cpu load and gpu load?

Okay, well I think I've found a candidate for "worst-case scenario" as far as microstutter goes. The heaven benchmark seems to really make the cards sweat (~100% load), and microstutter like crazy while they're at it.

Running at 1920*1200, with 4xAA, 16xAF, and starting a 60s FRAPS benchmark right as I start the benchmark in heaven, I get the following:


Normal tessellation, render max 3 frames ahead:
http://img214.imageshack.us/img214/531/heaven1.png

Extreme tessellation, render max 3 frames ahead:
http://img594.imageshack.us/img594/8...erme3ahead.png






Choosing instead to render 5 frames ahead, I see an improvement, albeit very slight:

Normal tessellation:
http://img831.imageshack.us/img831/4158/heaven2.png

Extreme tessellation:
http://img831.imageshack.us/img831/3...erme5ahead.png


I have to say, as I watched the benchmark unfold I KNEW the value was going to be high. I mean, it seemed pretty smooth overall, but for me 60fps is usually rock-solid (by eye anyway). In this, I saw the framerate counter at ~74, 75, and I could still tell that it wasn't perfectly smooth. As object passed by they seemed to be just a little jerky. Looking more closely at the frametimes file, there is some pretty poor behaviour in there. Not quite as bad as the plot I posted above from the 5870 x-fire vantage run, but still pretty disappointing.

Demonkevy666, I'm not sure exactly how to plot the CPU load... I can take a screengrab of the GPU loads from afterburner easily enough, but the output from coretemp isn't so straightforward as to allow a simple plot in excel.

It's been a long time since I've run the Heaven benchmark, but I don't recall that much microstutter :confused:

Anyway, benchmarks are just benchmarks. I wouldn't focus on them too much if I were you.

Another thing, use the 259.32 drivers. They are the best drivers I've used so far for my 480s; especially for Crysis.

The 200xx drivers are actually quite immature at this stage, even the official ones. Nvidia is supposed to come out with the 260xx drivers in a few days, so hopefully there'll be some more performance improvements and bug fixes.

Quote:

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Originally Posted by Carfax

Anyway, benchmarks are just benchmarks. I wouldn't focus on them too much if I were you.

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I agree... But my main aim in doing this stuff is to create awareness of microstutter as a real "performance detracting" issue, perhaps compile enough data to take to some review sites, who just might be in a position to press nvidia / ATI to do something to fix it. A pipedream probably, but it kind of annoys me that an issue like this exists.

I'll try out the 259.32 drivers when I get chance. I can imagine they improve performance, but to be honest I doubt they will affect microstutter, which seems to be a native AFR-related issue.

The key problem that I see with research like this is the amount of resistance you will meet from some members here tied to the hardware community. *ESPECIALLY* if it can be shown on xyz card that SLI or Crossfire yields no benefit when you factor observed frames vs actual frames per second gains from adding another card.

It is quite likely that what you may in the end prove is what a lot of us m-gpu old timers say that once you reach a certian point adding more cards detracts from peformance not helps which is most apparent when running Tri-SLI or Quad-Fire

It will also be interesting to see the other theory that microstutter is tied to PCI-E satuation when you compare the difference between say an 8x slot vs 16x slot etc etc. Which is why you see some say that increasing your PCI-E frequency, HTT or QPI helps to reduce microstutter.

Overall very interesting and what you describe matches my personal experience.

Nice work here. Funny how nvidias tessellation causes bad microstutter. Did you run it single card?

It would be good to put numbers to this issue. Especially with our own in house testing. I have access to 460sli I can post results in a few weeks though.

@Oztopher: which driver did you use? I am thinking 10.8 makes crossfire more interesting.

I'd also like to see 4870x2/5970 numbers too!

Quote:

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Originally Posted by damha

Nice work here. Funny how nvidias tessellation causes bad microstutter. Did you run it single card?

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For reference, single GPU result with heaven benchmark. Same settings as above (1920*1200, 4xAA, 16xAF, normal tessellation, stats on the first 60 seconds of the benchmark):

http://img413.imageshack.us/img413/5...nsinglegpu.png


More microstutter than I've seen with any other single-GPU result, but still pretty low.

I have to say, unfortunately it isn't just nvidia cards that exhibit this behaviour. The worst microstutter results so far have come from a tri-fire 5970+5870 setup (38-48% MS index).



Sentinal: I agree that it's always hard to get across a message that people don't want to hear. Hell, I don't really want it to be true, but it is, and ignoring it won't improve the situation in the future. My hope is that with enough results gathered on enough different configurations, the evidence will become irrefutable. If I had the time and cash I'd buy a whole load of hardware and do a proper analysis and formal results writeup. But unfortunately I don't, so anyone out there who can run this test is appreciated :)

As for PCI-e and QPI frequency, well I will have a play around with these, but I really don't see how it can have a major effect. The microstutter comes from a lack of control in when frames are output, in AFR mode. What is needed to fix it is some form of communication between the two GPUs to more effectively time the frame outputs, or better yet, a rendering method that has all GPUs working on a single frame (SFR, tiling etc).

Quote:

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Originally Posted by damha

@Oztopher: which driver did you use? I am thinking 10.8 makes crossfire more interesting.

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Yep i'm on 10.8. Haven't had a single problem with drivers, yet. I always make sure they're uninstalled/installed properly, i.e. express uninstall, reboot, run driver sweeper, reboot, delete all ATI folders etc. then run the ccleaner registry cleaner a few times (always picks up a few ATI reg files, even after running driver sweeper), then install new drivers.

Hmm, not sure how accurate this test is.. I just ran the Heaven benchmark (2.0) and this was my result:

http://a.imageshack.us/img265/7522/heavenh.png

This was with maxed out settings at 2560x1600 resolution, 4xAA, 16xAF, extreme tessellation etc, CPU at 4ghz, and 480s at 850/1700/4200..

The stutter index is high, but from what I could discern, the benchmark ran pretty smooth.

Quote:

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Originally Posted by Carfax

Hmm, not sure how accurate this test is.. I just ran the Heaven benchmark (2.0) and this was my result:

http://a.imageshack.us/img265/7522/heavenh.png

This was with maxed out settings at 2560x1600 resolution, 4xAA, 16xAF, extreme tessellation etc, CPU at 4ghz, and 480s at 850/1700/4200..

The stutter index is high, but from what I could discern, the benchmark ran pretty smooth.

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The tool is accurate - it just applies simple statistics to a FRAPS framelog. the exact procedure applied is given in the readme, IIRC.

The reason that it looked smooth is that your framerate is so high anyway. Check the apparent framerate - even taking microstutter into account, your "microstutter-free equivalent" framerate is 107fps. This should be pretty smooth. Like I said, the real-world effect of microstutter is to effectively reduce your framerate. If the framerate is sufficiently high, the game will still be smooth.


... But I have to ask - how in the hell are you getting those kinds of framerate at 2560, 4xAA, 16xAF?! Particularly with extreme tessellation. I get less than half that over the benchmark at 1920 resolution, and that seems to tie in with what others are getting...

Quote:

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Originally Posted by Arseface

... But I have to ask - how in the hell are you getting those kinds of framerate at 2560, 4xAA, 16xAF?! Particularly with extreme tessellation. I get less than half that over the benchmark at 1920 resolution, and that seems to tie in with what others are getting...

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Thats what I'm saying. There's no way my framerate was that high! :shrug:

I'll run it again later and double check.

Make sure you only run the FRAPS benchmark in-game. A few seconds of the loading screen, at 3000+ fps, will really skew the results.

Quote:

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Originally Posted by Arseface

For reference, single GPU result with heaven benchmark. Same settings as above (1920*1200, 4xAA, 16xAF, normal tessellation, stats on the first 60 seconds of the benchmark):

http://img413.imageshack.us/img413/5...nsinglegpu.png


More microstutter than I've seen with any other single-GPU result, but still pretty low.

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Which confirms my speculation. The card is dropping frames for tessellation work which means optimization. Not a bad thing as long as the framerate is high and ms is not noticable.

Although.. are you sure your formula isn't buggy? The "Global Average Timeframe" is pretty high in that single card run. It's probably due to the low fps, but never hurts to ask :)

Quote:

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Originally Posted by Oztopher

Yep i'm on 10.8. Haven't had a single problem with drivers, yet. I always make sure they're uninstalled/installed properly, i.e. express uninstall, reboot, run driver sweeper, reboot, delete all ATI folders etc. then run the ccleaner registry cleaner a few times (always picks up a few ATI reg files, even after running driver sweeper), then install new drivers.

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Thanks :)

I'd be curious to see if microstutter is more noticeable visually on 120hz displays. I must say I noticed it quite a bit with my old 4870x2 and to a slightly lesser extent on 2 260s but this was only at 60hz. I personally enjoyed Crysis more on a single 260 than a 4870x2 interestingly enough and I'm confident the microstuttering was behind this.

Like has been said its not that noticeable at higher framerates but in games which are more taxing ( ie the types of games where multi gpu setups would be most desireable ) it is much more noticeable.

Well you have how bad it microstutters, then you have how fast its running.

Lowfps + high microstutter = fail
Highfps + high microstutter = doable
lowfps + low microstutter = acceptable
highfps + low microstutter = win

I'm running 2x 5870's in cf and ran AVP for about 30-40 secs and these are my results.

http://i51.tinypic.com/2lt6l95.png

A nifty little program. Sure beats doing tens of graphs on Excel just to convince a bunch of people that avg FPS means nothing unless you are sure that no microstuttering occurs.

I just deleted a really big bunch of framtime data I had on my harddrive. I had a few really wild ones using Unigine, Stone Giant and Stalker:CoP.

Here's a graph of one run I had (Single 5870, converted to fps from frametimes):
http://img517.imageshack.us/img517/2605/sg5870.png
The stutter percentage would probably be pretty low on this one but it sure is very visible to the eye as it periodically looks like a 20-40% frop in framerates. Alot of people don't believe their eyes because the FPS number stays the same.

FC2 used to be one of the most microstuttering games out there, it was obvious even on a single GPU. Eventually Nvidia did fix it though in some driver release, so it's at least in part fixable if they'd bother to, but most likely they won't cause it might lower the "real" fps result. I hear Stalker is one good (bad) example of ms too.

Lot's of people are probably considering to go GTX 460 SLI, but if microstutter takes that 20% off your fps it's not really as good as GTX 480 now is it? Of course it's dependant on the game and drivers and whatnot. All in all if you go SLI or CrossFire, you should go big time, as in GTX 480 SLI, not some dual 5770 setup where you'll end up with low fps and high stutter.

Quote:

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Originally Posted by Pantsu

Lot's of people are probably considering to go GTX 460 SLI, but if microstutter takes that 20% off your fps it's not really as good as GTX 480 now is it? Of course it's dependant on the game and drivers and whatnot. All in all if you go SLI or CrossFire, you should go big time, as in GTX 480 SLI, not some dual 5770 setup where you'll end up with low fps and high stutter.

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I had a 5870 crossfire configuration for a while and it was actually worse than a single card. When looking at frametimegraphs it was clear that the experienced fps couldn't possibly be more than 20% higher compared to a single card. What made it worse was the randomness of the stuttering. To me crossfire was a huge downgrade... higher numbers but even worse experienced performance :down:

Here's a shot of one my old FC2 .csv files. This was done on a single GPU, and was the worst case of a dozen tests.

http://i406.photobucket.com/albums/p...da/stutter.png

You can imagine what it would look like on dual gpu setups. Somewhere between April and July though Nvidia addressed the problem, and now it's smooth with max 5% difference.

Thanks for the results guys :)

Interesting to see some real microstutter from single GPU setups, even if it was due only to a game-specific driver issue. I think there have been similar problems with Fallout 3 in the past (I don't know if they have been fixed by now or not). And yes, I completely agree that the whole "SLI 260s vs a single GTX480" issue is the place where microstutter comes into play the most. It really does make a difference to the price : performance payoff of the two setups. When you're adding a second GTX480 it's just a case that you're not getting quite the performance increase you expect, but the bump is still significant. But I would never double up slower cards - the real-world performance will always be better with a single faster card.

Quote:

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Originally Posted by Zaxis01

I'm running 2x 5870's in cf and ran AVP for about 30-40 secs and these are my results.
http://i51.tinypic.com/2lt6l95.png

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Great to see that there are at least some circumstances where the microstutter from 5870 x-fire setups is minimal :) I found a similar thing with the GTX480s on crysis 1920*1200.

Any chance you could run the heaven benchmark? :)

Quote:

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Originally Posted by damha

Although.. are you sure your formula isn't buggy? The "Global Average Timeframe" is pretty high in that single card run. It's probably due to the low fps, but never hurts to ask :)

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You can see that the global average frametime and framerate are equivalent:

framerate(fps) = 1000 / frametime(ms)

Quote:

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Originally Posted by janolle

Here's a graph of one run I had (Single 5870, converted to fps from frametimes):
http://img517.imageshack.us/img517/2605/sg5870.png
The stutter percentage would probably be pretty low on this one but it sure is very visible to the eye as it periodically looks like a 20-40% frop in framerates. Alot of people don't believe their eyes because the FPS number stays the same.

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Wow, that looks terrible...

And yes, that would have a relatively low microstutter index, particularly as I cull the worst 1% of frametime variations from my formula (in order to account for paging etc).

Not quite sure what's going on there if it's a single GPU run. Obviously some major issue with whatever game that is. Either that or constant DRAM to VRAM paging?

Quote:

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Originally Posted by Arseface

Not quite sure what's going on there if it's a single GPU run. Obviously some major issue with whatever game that is. Either that or constant DRAM to VRAM paging?

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I have no idea what causes that but a closer look shows that it's almost excatly the same thing as microstuttering in cf (a slower frame followed by a quick one). Microstuttering isn't just a multi-gpu problem... although it's ALOT worse with 2 or more GPUs. ;)

Heres a comparison of single vs. cf in Stalker:CoP.
http://img522.imageshack.us/img522/7...pbenchfull.png

OK I did another run, and this one seems to be much more accurate. I think I left FRAPS running after the first benchmark had actually finished (exit screen) which was why my results were whacked!

Anyway, same settings as the first one, Heaven benchmark (2.0) @ 2560x1600 4xAA 16xAF, extreme tessellation etc, with 480s overclocked to 850/1700/4200.

http://a.imageshack.us/img714/7959/heavena.png

I can't say I noticed any microstuttering with the naked eye. The benchmark appeared to run quite smooth.

I also had my max pre rendered frames set to 6. As I mentioned earlier, if you're running SLi, it's best to have that setting at either 5 or 6 to get the best gaming experience and performance.

Makes everything a lot smoother...or at least for me it does. :yepp:

Quote:

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Originally Posted by Carfax

OK I did another run, and this one seems to be much more accurate. I think I left FRAPS running after the first benchmark had actually finished which was why my results were whacked!

Anyway, same settings as the first one, Heaven benchmark (2.0) @ 2560x1600 4xAA 16xAF, extreme tessellation etc, with 480s overclocked to 850/1700/4200.

http://a.imageshack.us/img714/7959/heavena.png

I can't say I noticed any microstuttering with the naked eye. The benchmark appeared to run quite smooth.

I also had my max pre rendered frames set to 6. As I mentioned earlier, if you're running SLi, it's best to have that setting at either 5 or 6 to get the best gaming experience and performance.

Makes everything a lot smoother...or at least for me it does. :yepp:

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I'm not sure if fraps measures what you see on your screen when using pre-rendered frames. It's possible that it measures the output before the buffer. Pre-rendering will of course smoothen the experience but it also causes lag that most gamers don't like. Renderin 5 frames ahead will cause a 100ms lag at 50fps and that's huge!

Quote:

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Originally Posted by janolle

I'm not sure if fraps measures what you see on your screen when using pre-rendered frames. It's possible that it measures the output before the buffer. Pre-rendering will of course smoothen the experience but it also causes lag that most gamers don't like. Renderin 5 frames ahead will cause a 100ms lag at 50fps and that's huge!

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I only notice more lagging or jerkiness when I go above 6. Setting it to 5 or 6 though, makes my gaming experience smoother with no noticeable lag compared to the default value of 3.

I'm sure the type of CPU you have makes a difference as well. I doubt using such high values with dual cores (or S775 quadcores) for instance would improve gameplay. Most likely, it would degrade it.

Quote:

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Originally Posted by Carfax

I'm sure the type of CPU you have makes a difference as well. I doubt using such high values with dual cores (or S775 quadcores) for instance would improve gameplay. Most likely, it would degrade it.

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I don't mean to be rude but could you explain this to me?

I don't see how a framebuffer could be affected by cpu performance in any way. As I see it it's a simple matter of framerates. :confused:

More cpu-cores -> more microstutter. When use only 1 core, you get almost none of microstutter.

Quote:

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Originally Posted by FinBenton

More cpu-cores -> more microstutter. When use only 1 core, you get almost none of microstutter.

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Well this is true, but only because using a single CPU thread you'll almost always be CPU limited. And as I already demonstrated, when the CPU is the limiting factor then the degree of microstutter is always low, because the GPUs are waiting for the CPU to finish its workload every frame, and therefore sync to the regular output from the CPU.


Case in point; Crysis 2560*1600, 4xAA with only a single CPU thread active:

http://img688.imageshack.us/img688/2...nglethread.png


As you can see, even at this resolution the GPUs were not at full load. And the result (37fps) is slower than the eight-thread result I posted earlier, even taking into account microstutter (apparent framerate 44.9, down from 51.9).

I'm sure you could achieve the same effect by under-clocking the CPU, but neither is very attractive as a solution.

Quote:

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Originally Posted by janolle

I don't mean to be rude but could you explain this to me?

I don't see how a framebuffer could be affected by cpu performance in any way. As I see it it's a simple matter of framerates. :confused:

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Hehe, I'm not sure I'm qualified to explain it to you.. I was merely postulating in truth, since SLI rigs (Crossfire too in fact) perform much better on Core i7 than on previous CPU architectures.

Click here for an example.

And the above link was done with 280s. Can you imagine what it's like with 480s, which are roughly twice as powerful? :eek:

I suppose it has to do with the CPU's abilities to "feed" the GPUs. The multithreaded nature and high data throughput of the Core i7 allows it to send data faster to multiple GPUs so they don't have to wait. :shrug:

Increasing the amount of framebuffers increases the CPU workload, but if the CPU isn't fast enough to keep up, then I would assume performance would suffer....much as it does when I go above 6 framebuffers.

Using high end cards like the 480 or HD 5870 in multi GPU configs with anything less than a Core i7, hampers their performance though to be quite honest..

Quote:

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Originally Posted by Carfax

Hehe, I'm not sure I'm qualified to explain it to you.. I was merely postulating in truth, since SLI rigs (Crossfire too in fact) perform much better on Core i7 than on previous CPU architectures.

Click here for an example.

And the above link was done with 280s. Can you imagine what it's like with 480s, which are roughly twice as powerful? :eek:

I suppose it has to do with the CPU's abilities to "feed" the GPUs. The multithreaded nature and high data throughput of the Core i7 allows it to send data faster to multiple GPUs so they don't have to wait. :shrug:

Increasing the amount of framebuffers increases the CPU workload, but if the CPU isn't fast enough to keep up, then I would assume performance would suffer....much as it does when I go above 6 framebuffers.

Using high end cards like the 480 or HD 5870 in multi GPU configs with anything less than a Core i7, hampers their performance though to be quite honest..

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Pre-rendering of frames simply dealys the output a certain amount of frames. The cpu has very little to do with that.

A faster cpu (or lower detail settings) may get higher framerates and that will reduce the lag that buffering causes. Even at 100fps the lag with 6 pre-rendered frames is unacceptable for games that require instant response.


At this time it's a choice between instant response or microstutter. Let us hope that it will work better in the future.

Quote:

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Originally Posted by janolle

At this time it's a choice between instant response or microstutter. Let us hope that it will work better in the future.

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I found only a minor improvement by increasing the number of frames rendered ahead (see above).

As far as I see, vsync is the only way to reduce microstutter. Which, I guess, also increases response time (though not by as much). So it's a tradeoff between microstutter, or reduced performance and somewhat increased response time.

I had heaven in windowed mode and I noticed one sit was a bit smoother then other in crossfire. :/
anyone know where I can change the driver to do super tiling in stead of AF rendering ?

seem like it dose super tiling in windowed and AF in full screen.

Quote:

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Originally Posted by demonkevy666

I had heaven in windowed mode and I noticed one sit was a bit smoother then other in crossfire. :/
anyone know where I can change the driver to do super tiling in stead of AF rendering ?

seem like it dose super tiling in windowed and AF in full screen.

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http://www.xtremesystems.org/forums/...d.php?t=252301
That will do it, I think.

Heaven Benchmark Using 2x 5870's

http://i52.tinypic.com/1267669.png

Thanks zaxis :)

Looks like the 5870 x-fire setup is just as bad as SLI GTX480s when it comes to microstutter though :(

Quote:

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Originally Posted by Zaxis01

I'm running 2x 5870's in cf and ran AVP for about 30-40 secs and these are my results.

http://i51.tinypic.com/2lt6l95.png

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Dont know what is my problem but im getting much worse microstuttering on AVP benchmark, might be different while playing?

CPU stock:
http://i9.aijaa.com/b/00020/6662116.png

CPU overclocked:
http://i4.aijaa.com/b/00021/6662117.png

Benchmark it self doesnt look so bad, but those numbers are really bad..:down:

If you're running at settings which are largely GPU-limited, then you will see the microstutter (as you have found above).

In CPU-limited scenes you will see very low microstutter, as the GPU output syncs to the CPU, which it is waiting for after each frame.

Given that you have gained (virtually) nothing in this benchmark from overclocking the CPU, I would guess you're largely GPU-limited in this case. I suspect the scene that Zaxis benchmarked was largely CPU limited.


... Looks like I don't need the entire game in order to run the benchmark, so I'll grab it and do some comparisons using the GTX480s. Good to see more ATI results coming in now though - just what I'm after in order to compare the two technologies :) It would help if you could let me know the exact settings you used (resolution, AA/AF, detail levels etc), and when you started the FRAPS benchmark / how long you ran it for, so I can replicate as close as possible :)



Edit:

1920*1200, 4xAA, 16xAF, textures=very_high, SSAO=on, tessellation=on, shadow quality = high.

Ran the FRAPS bench for the entire run (stopped as the benchmark fades out)



http://img43.imageshack.us/img43/569...crostutter.png



Ouch... Pretty bad :( Although, as above, the sufficiently high framerate made it seem pretty smooth.

Quote:

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Originally Posted by Arseface

Thanks zaxis :)

Looks like the 5870 x-fire setup is just as bad as SLI GTX480s when it comes to microstutter though :(

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Did you see my earlier scores?

http://a.imageshack.us/img714/7959/heavena.png

Thats for the heaven benchmark, @ 2560x1600 4xAA 16xAF, extreme tessellation etc..

A value of 18% isn't too bad is it?

Quote:

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Originally Posted by Carfax

A value of 18% isn't too bad is it?

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I would say that 18 is easily noticed if you pay attention to what fps readings you're getting and how it looks. What you see is an average performance drop of 18% compared to the fps reading you're looking at. And that's an average reading wich it is probably much worse in some situations.

I once saw a nifty little program that you can test microstuttering with different variables. You should try it out if you can find. I think it's made by some german guy.

Yeah, for the heaven benchmark that's not too bad at all. I've been getting 20-25 for the most part, at 1920*1200 4xAA 16xAF. May still be fairly noticeable though, at a moderate framerate.

What drivers are you on? 258.96?



edit: This plot I posted earlier is a reasonable example of the framerate variation you can expect with a microstutter index of around 18-20:

http://img227.imageshack.us/img227/6...livssingle.png



edit: Just computed the microstutter index in excel for the (blue) dataset shown above, and it comes out as 18.6%. This excludes the first and last 3 data-points, as these are needed to form the local average for the adjacent points. So yeah, the above should give you a very good idea of what ~18% MS looks like. Although obviously it will vary over the course of the benchmark, some parts being worse and some parts being better.

Quote:

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Originally Posted by janolle

I once saw a nifty little program that you can test microstuttering with different variables. You should try it out if you can find. I think it's made by some german guy.

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Sounds ace... I certainly wasn;t aware of any such program.

If you come across it then please post a link :)

Quote:

---

Originally Posted by Arseface

If you're running at settings which are largely GPU-limited, then you will see the microstutter (as you have found above).

In CPU-limited scenes you will see very low microstutter, as the GPU output syncs to the CPU, which it is waiting for after each frame.

Given that you have gained (virtually) nothing in this benchmark from overclocking the CPU, I would guess you're largely GPU-limited in this case. I suspect the scene that Zaxis benchmarked was largely CPU limited.


... Looks like I don't need the entire game in order to run the benchmark, so I'll grab it and do some comparisons using the GTX480s. Good to see more ATI results coming in now though - just what I'm after in order to compare the two technologies :) It would help if you could let me know the exact settings you used (resolution, AA/AF, detail levels etc), and when you started the FRAPS benchmark / how long you ran it for, so I can replicate as close as possible :)



Edit:

1920*1200, 4xAA, 16xAF, textures=very_high, SSAO=on, tessellation=on, shadow quality = high.

Ran the FRAPS bench for the entire run (stopped as the benchmark fades out)



http://img43.imageshack.us/img43/569...crostutter.png



Ouch... Pretty bad :( Although, as above, the sufficiently high framerate made it seem pretty smooth.

---

I used the same settings but my rez was 1080p as you did, and i had 1,2GHz overclock on that second run so it sure is gpu limited. I'll test what kind of result FC2 (games own benchmark-tool) with minimum DX10 settings gives @ 1080p, i think it's more CPU limited. Do same if you have that game.

Update: Far Cry 2 with minimum graphical settings (DX10 all off or lowes settings) there are almost non microstuttering as you can see:
http://i7.aijaa.com/b/00344/6664188.png

Atleast that confirm's that microstuttering and gpu limiting are walking hand by hand..

Quote:

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Originally Posted by Arseface

Sounds ace... I certainly wasn;t aware of any such program.

If you come across it then please post a link :)

---

Found it. http://www.computerbase.de/downloads...er-single-gpu/
It's a simple program that shows moving circles. You can adjust the framerate and the delay of every other frame. Low delay value = big frametime difference. You can quickly change between "microstutter mode" and normal with the space button.

You'll really see the difference when moving your mouse...

EDIT:
Edit the settings file to set the right resolution.
A nice thing is that it also says what fps experience you're getting with the stutter. I think it's close to the % of stutter that we are measuring here.

Quote:

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Originally Posted by Asmola

Atleast that confirm's that microstuttering and gpu limiting are walking hand by hand..

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Yep, it makes logical sense that a CPU-limited scene would be virtually free from microstutter, and the results we have so far only work to confirm that :)

I'm afraid I don't have Far Cry 2, but I've done plenty of runs with crysis, incrementally dropping the resolution and looking at the GPU load in afterburner, and I find the same as you have shown with FC2; that as GPU load drops below around 90%, then microstutter rapidly disappears.

Quote:

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Originally Posted by janolle

Found it. http://www.computerbase.de/downloads...er-single-gpu/
It's a simple program that shows moving circles. You can adjust the framerate and the delay of every other frame. Low delay value = big frametime difference. You can quickly change between "microstutter mode" and normal with the space button.

You'll really see the difference when moving your mouse...

EDIT:
Edit the settings file to set the right resolution.
A nice thing is that it also says what fps experience you're getting with the stutter. I think it's close to the % of stutter that we are measuring here.

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What a fantastic little program - thanks! :)

Yeah, the "feels like" fps should use the same formula as I do - it's fairly logical once you know the true framerate and the maximum delay between frames. The only extra steps my program takes is to estimate the local average framerate based on a smoothing over surrounding frames (since FPS in-game is constantly changing, regardless of microstutter), and perform some basic statistics to average out the amount of microstutter (which will also be changing frame-by-frame).

It's worth noting, though, that this guy's program will give a "best case" scenario, where you have a uniform irregularity in frame output. In the real world, for a given "feels like" FPS there will be some patches where the performance is even worse (as well as patches where it is better).

With my gtx 295, I dont see any significant difference between 1 and 2 gpus enabled in the variance in frame rendering (or microstutter as you are calling it). When benchmarking crysis, 3dmark6, cod, or any other games, I see varying framerates with both 1 and 2 gpus, and graphs look very similar with 1 vs 2 gpus enabled graphically and games look same visually, unless 1gpu gets framerates too low then it stutters.

http://img43.imageshack.us/img43/868...ual100frms.jpg

Crysis with everything on highest level, varying frame rates are similar between single and multiple (magnitude roughly same, though sli appears more since x axis slightly different). These runs were from an earlier discussion where some were saying when you straffe instead of walk or run in crysis you see more microstutter, though I never visually saw microstutter in that game. Though I can cherry pick runs and show sli with less variance or vice versa.

Point is, I cant reconcile varying frame rates on graph with visually seeing microstutter, nor can I differentiate 1 vs 2 gpus varying frame rates. But I will give your program a whirl and see if it shows any difference between 1 vs 2 gpus on mine.

http://img707.imageshack.us/img707/3...ownslicrys.jpg

http://img697.imageshack.us/img697/2...own1gpucry.jpg

Great little tool guys, here is 5850 Tri-CFX playing the BC2 level snowblind from start to finish, max settings 8xAA DX11 1080p

http://img72.imageshack.us/img72/8107/43928517.jpg

And here is BC2 MP map valparaiso in rush mode, only played until the first 2 bombs were blown (~10mins gameplay)

http://img811.imageshack.us/img811/232/36792132.jpg


And the Mafia2 benchmark
http://img101.imageshack.us/img101/7003/mafia2l.jpg

So when you're CPU-limited you get less microstutter? Sooo... let's get to downclocking?

3Dmark 06 GPU Test 1 Return to Proxycon

http://img405.imageshack.us/img405/2999/59908303.jpg

The Stone Giant DX11 Benchmark.

http://i51.tinypic.com/mwp6jc.png

demowhc - We have established that there is very little microstutter in CPU-limited scenarios, as frame output is tied to the regular output from the CPU. Of more interest is the 'worst case' scenario, where the GPU is the limiting factor. I would love to see some tri-fire runs from crysis at 2560*1600 4xAA, or the heaven benchmark. Thanks for taking the time to do the runs you've posted already though :)


rge: - The plots you have are pretty interesting. I must say, in my testing I haven't come across any scenarios where the single-card stutter is that bad; the worst case being the heaven benchmark with extreme tessellation. I can certainly "cherry pick" a few consecutive frames from a framelog that will look bad, but nothing representative. Not suggesting that's what you have done - just pointing out that things seem to have improved as far as single cards setups go :) Perhaps a driver-based correction?

As for the multi-GPU results, certainly it's possible to get very consistent framerates with multi-GPU setups - any time that the GPUs are running at less than 100% load the output is very uniform. This is to logically to be expected, and we have plenty of runs to back this up. But again, I find a very consistent microstutter in GPU-limited game scenes. I have yet to find any with less than ~15% microstutter. Of course, I can only directly test the GTX480s, but results from other users seem to suggest a similar thing with ATI-based setups.

In terms of the frametime variation in the crysis plots you posted, taking "walking straight" as an example, the magnitude of variation with SLi is around 8ms, on an average of 12ms [so 4ms average deviation; implies around 33% MS index]. On single GPU, the variation is around 4ms against an average of 18ms [so ~2ms average deviation; ~ 11% MS index]. The absolute variation in frametime is not so different between the two setups, but the relative variation is much bigger. The relative variation is the important factor in quantifying the effect of microstutter. To see this fact more clearly, consider, for example, a consistent 10ms deviation: This is relatively insignificant at a 100ms average; i.e 10fps appears like 9fps, but at a 10ms average; i.e. 100fps, it represents an effective halving of the framerate, since the gap between frames is either 20ms or zero.

just cause 2 here is sli with stutter index of 36 (1st pic), and single gpu enabled with 18, so sli was 2x in this game. Single card runs varied from 8 to 18, depending on higher or lower detail settings or just variability, didnt run enough times to check. SLI in thirties regardless of settings.

wish I still had crysis would be interesting to use your tool on, I always had to use excel, or just csv outputs that i ran, but dont feel like reinstalling just to run that benchmark.

I just had a thought, how about the Hard drives? SSD VS Mechanical, I mean if you think about it, it might be so the hardrives aren't keeping up too. Though highly unlikely, just a thought.

rge: Thanks for the Just Cause 2 info mate :) I'm not at home right now, but I have JC2 so I can do some 480GTX comparisons tomorrow. I still find it a little surprising that the single cards show such a (relatively) high degree of microstutter, but clearly they do. That's twice as much MS as I've managed to find so far with a single GPU. Perhaps I haven't been testing the right things (I've focussed 90% on multi-GPU), or perhaps things have improved with this generation of cards. And yeah, I agree - no point reinstalling crysis just to do a few microstutter runs!


Cookiesowns: Unfortunately I don't think that HDD speed will have much to do with it. Once the game scene has been loaded into the system memory, the HDD doesn't have much bearing on the rest of the run. Besides, the computation of the MS index culls off the highest 1% of variations. This was done so as not to bias the results with "hitching", or other loading / paging type issues.

Quote:

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Originally Posted by Arseface

Cookiesowns: Unfortunately I don't think that HDD speed will have much to do with it. Once the game scene has been loaded into the system memory, the HDD doesn't have much bearing on the rest of the run. Besides, the computation of the MS index culls off the highest 1% of variations. This was done so as not to bias the results with "hitching", or other loading / paging type issues.

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On that note high mhz ram will increase my fps, along with tighter timings.
I think it comes down to how it renders the screen it would less noticed when it split in half by two card vs each frame rendered at once.

Quote:

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Originally Posted by demonkevy666

On that note high mhz ram will increase my fps, along with tighter timings.
I think it comes down to how it renders the screen it would less noticed when it split in half by two card vs each frame rendered at once.

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Certainly.

A split-frame rendering method (or "super-tiling" or any other method that has all GPUs working on the same frame at once) should do away with microstutter entirely. It should act like a single GPU.

Stalker CoP and Metro 2033 were pretty bad with Tesselation enabled, about 18%, but with tesselation disabled they were back under 5%. With vsync though, how I play them, they are very steady under 2%.

Heaven 2.1 was a joke with tesselation set to normal, 4xAA 16xAF at a whopping 54% :eek: taking the frame rate from mid 80's down to an apparent 40 something fps, it ran like a mofo as you can imagin.. :ROTF:

Ran a loop of Crysis bench at 4xAA 16xAF DX10 VH 1080p

http://img340.imageshack.us/img340/5824/23523936.jpg

demowhc you must be running very low res or that 4.4ghz oc is doing you a lot of good.

Quote:

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Originally Posted by damha

demowhc you must be running very low res or that 4.4ghz oc is doing you a lot of good.

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He's still largely CPU-limited.

In my first post I demonstrated that, using dual GTX480s, crysis is just beginning to become CPU bound at 1920*1200, 8xQ AA, 16xAF, very high. The MS index was around 8%. If I drop the settings slightly, the MS index drops also. Here, he is running at a lower resolution, with less AA, and a triple GPU setup. I would expect CPU-restriction here as well.

The heaven result is more in-line with that I would expect from a triple-GPU setup, being an almost-pure GPU benchmark. I suspect you will see similar results from crysis at 2560, 4xAA (you can run that on lower res monitors - it will downscale).

Metro2033 surprises me though - that should be pretty heavily GPU limited, and is still showing good results. I've been threatening to buy this game anyway, so perhaps I'll grab it and test it too. And yes - with double-buffer vsync enabled the microstutter should all-but disappear in any game.

I use 1080p because I only play games with 60+ fps

I'll try Crysis with 24xEDSSAA in dx9 very high, should put some more strain on the GPU's.

Apart from that I dont have any demanding titles, except ArmA2 which has vsync forced on by default, but runs at a steady 60fps vsync at 3840x2160.

BTW, I actually got a higher frame rate in Heaven than the Crysis bench, so which is more GPU limited?

Here is Crysis bench with 24xEDSSAA

http://img31.imageshack.us/img31/6064/untitleyyyyd.jpg

I'm fairly happy all my games run very smooth, the only problem I have is with Heaven benchmark, lucky I dont play Heaven I guess :P

oh wait I just saw you said you can run crysis in 2560 and downscale, will try it :)

Must run out of Vram because Crysis bench craps itself at 2560x1440, even tried dropping texture res and although it was better it still died in the ass when overlooking the island :(

The best I can give you in Crysis bench at max settings is 2048x1152 (12xEDAA 16xAF DX10) without running out of Vram.

http://img521.imageshack.us/img521/8...hhhhhhhhhd.jpg

I was playing some Metro 2033 and even at 40 fps in a couple of areas the gameplay felt a lot choppier than it should have. I was wondering if it was this microstutter that I've heard so much about. I saw this thread and gave this tool a shot and this is what I saw. This is a benchmark in one area that was annoying me.

I am running 6950 crossfire on an Msi P55GD65 and an i5 760 at 4ghz.

http://i308.photobucket.com/albums/k...rMetro2033.png

Quote:

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Originally Posted by BababooeyHTJ

I was playing some Metro 2033 and even at 40 fps in a couple of areas the gameplay felt a lot choppier than it should have. I was wondering if it was this microstutter that I've heard so much about. I saw this thread and gave this tool a shot and this is what I saw. This is a benchmark in one area that was annoying me.

I am running 6950 crossfire on an Msi P55GD65 and an i5 760 at 4ghz.

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hi, i had the same personal experience with 2*hd6950@6970 in metro2033: at <40fps in crossfire feels as laggy/jumpy as with one card at ~25fps, the same goes for the stalker games...there are some games which are not so prown to microstuttering, but definitly metro & stalker series are more likely to microstuttering...
greets

Quote:

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Originally Posted by MaxMax77

hi, i had the same personal experience with 2*hd6950@6970 in metro2033: at <40fps in crossfire feels as laggy/jumpy as with one card at ~25fps, the same goes for the stalker games...there are some games which are not so prown to microstuttering, but definitly metro & stalker series are more likely to microstuttering...
greets

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Thanks, it's good to know that I'm not alone. It's not bothering me too much since there isn't a single gpu solution that could get anywhere near the framerates that I'm seeing now.

I had noticed some slowdowns in Crysis as well that I would love to test with this tool.