[PCPer] Frame Rating Part 3: First Results

PCPer has been looking into some new ways of testing smoothness. They just released an article on their process so far with some very interesting results.

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If you haven't been following our sequence of stories that investigates a completely new testing methodology we are calling "frame rating", then you are really missing out. (Part 1 is here, part 2 is here.) The basic premise of Frame Rating is that the performance metrics that the industry is gathering using FRAPS are inaccurate in many cases and do not properly reflect the real-world gaming experience the user has.

Because of that, we are working on another method that uses high-end dual-link DVI capture equipment to directly record the raw output from the graphics card with an overlay technology that allows us to measure frame rates as they are presented on the screen, not as they are presented to the FRAPS software sub-system. With these tools we can measure average frame rates, frame times and stutter, all in a way that reflects exactly what the viewer sees from the game.

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Link

Interesting, I was doing some more reading on this issue regarding AMD crossfire, and apparently Radeon Pro can fix it:

http://www.tomshardware.com/reviews/...2,3329-11.html

Yeah, Toms just used a framerate cap. Sort of like when people use to use fps limiter in the 4870x2 days. It works great at eliminating stutter but when the framerate dips below that cap you'll still get microstutter.

Its a great workaround but not really a solution.

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Originally Posted by BababooeyHTJ

Yeah, Toms just used a framerate cap. Sort of like when people use to use fps limiter in the 4870x2 days. It works great at eliminating stutter but when the framerate dips below that cap you'll still get microstutter.

Its a great workaround but not really a solution.

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Tried dynamic vsync option?

This testing method is great for testing AFR, but it will be of limited usefulness for testing scissor or tiling. Personally, I'm a tiling fan even though it has the lowest scaling.

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Originally Posted by STEvil

Tried dynamic vsync option?

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The Tom's article was wrong. They were using dynamic framerate control, not dynamic vsync. Look at the Radeon pro screenshots that they were using. Dynamic vsync is similar to Nvidia's adaptive vsync. It just turns vsync off when it dips under your refresh rate. Very cool but doesn't help microstutter.

Dynamic framerate control afaik is just a hard cap like the old fpslimiter program. That I use all of the time but again its a workaround and not a real solution since if the framerate dips under that cap frame latency will become an issue again.


On that topic. I really do think that if AMD figures out a framerate smoothing option similar to what Nvidia uses it'll fix both the single card and afr stutter. If you look at techreport's old reviews with AMD's 6xxx series and especially 5xxx series they did very poorly with frametime consistency. What? The memory management system wasn't optimized for those cards either? I'm not buying into that excuse.

very damning. in bf3 at least, crossfire is garbage. the next time someone suggests crossfire, show them how it skips down to non-crossfire performance, making it pointless: http://www.pcper.com/image/view/2096...n=node%2F56621

Only reason I was suggesting crossfire recently was because of the prices on 7950s / 7970s compared to Titans and even GK104s.

Seems like the only decent high end is dual GK104s or a Titan atm then.

Crossfire is still very useful. When you can buy thee 7950s for less than the price of on Titan and then pop them onto a mid range board like the UD5h you can get a lot of power for your money. As long as you cap the framerate performance is smooth. Even then microstutter isn't always consistent so you won't see it in every game or all of the time in the games that you do.

This is definitely an issue that AMD needs to address and I'm glad that some review sites are placing more emphasis on smoothness.

Sure, but at what cost? I've been using a frame cap in the past when my experience with SLI was still very new, but the drawbacks are just too severe.

Because you need to cap fps at or around your minimum fps, you will waste a lot of performance in scenes where those minimum fps are exceeded. So basically most of the time. For example when playing Skyrim with SGSSAA, my fps could dip to the low 40s in dense foliage and forests, which was stuttery. I capped my fps to 40 then, but that meant losing a full 20 fps (I play at 60 Hz vsync) during most of my gameplay. I found that quite unacceptable and it can utterly destroy scaling, calling going with multiple GPUs into question in the first place. Value doesn't look that good, then.
The only thing I really like about RadeonPro and its fps cap is that you can adjust the value via hotkey while gaming. Doesn't solve the underlying problem, but it's more comfortable than having to alt-tab out of the game, changing the value and hoping the game didn't crash due to the task switch.

One of the main reasons I picked Nvidia this generation was adaptive Vsync and no longer having to have FPS capped to 30 when running Vsync.

I'm not sure how frame rate limiting works on AMD cards, but if it locks the FPS to anywhere below 45, then that's not good enough for me because I see stutter up to around 40 fps. I remember back when I had SLI I thought that the stutter I was seeing around 30-40 FPS was due to microstutter, but its still the same on a single 680 when I force my FPS to 35 for video capture..

And the prices on GTX 680s are still ridiculous, IMO if you need more than one then just get a Titan.

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Originally Posted by bamtan2

very damning. in bf3 at least, crossfire is garbage. the next time someone suggests crossfire, show them how it skips down to non-crossfire performance, making it pointless: http://www.pcper.com/image/view/2096...n=node%2F56621

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You are reading the chart completely wrong.

The variation you see on the Crossfire solution is ALL below 20ms, making it literally imperceptible to the end user.

Honestly, without perspective people can take these charts and have them completely misrepresent the information being provided. A card can do the bloody hokey pokey all over the place below 20ms and it wouldn't make one lick of difference since the actual REAL WORLD experience would still read as smooth.

20ms is slightly noticeable...
I know this from working with directsound buffers.
But forget about all that.

1000ms in a sec / 20ms of lag = 50fps max...
Does this 20ms include the monitor lag?, I don't know I should probably check the link lol.
I'm guessing it does.

Lets pretend for a sec here.
2x sli or cfx = 20ms of lag.
4x sli or cfx = 40ms of lag, or 25fps max per sec...
That's not good lol lmao...

I notice a little bit of "input" lag on a single monitor in farcry3 and dead island (dead island is way bad sometimes when driving, probably not the video card, probably my usb or something).

SKYMTL,
do you have actually tried SLI/CF for gaming, not just for benchmarking? These variations can and do affect playability depending on how perceptive you are. How can you make your absolute statements for all people?

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Originally Posted by boxleitnerb

SKYMTL,
do you have actually tried SLI/CF for gaming, not just for benchmarking? These variations can and do affect playability depending on how perceptive you are. How can you make your absolute statements for all people?

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Again, you are making a blanket statement.

Do rapid fluctuations affect gaming? YES. However, the microstutter you see is likely NOT below 20ms but rather higher than that. Typically when deltas of 10ms or more quickly fluctuate at 25ms and above, you'll see microstutter. Anything below 20ms and you'd either completely miss it or be VERY picky and go looking for it.

Let me reiterate:

- Below 20ms: unnoticeable
- Rapid, cyclical fluctuations above 25ms: you'll notice it
- Sudden "spikes" (non-cyclical) above 40ms: you'll notice it
- Grey area between 21ms and 25ms: debatable. Some will notice it while others won't.

I said "depending on how perceptive you are". So much for blanket statement...

The rest of your post is a blanket statement. You don't speak for everyone and you cannot possibly define what is generally noticeable and what is not.

If enabling normal vsync, does it totally eliminate stuttering in CF/SLI regardless of fps/hz?

I've tried plenty of Xfire / SLI setups before swapping to a single GK104, I noticed no difference in smoothness with the same FPS in any games.

Any game running at 30-40 FPS was still stuttering to me with both a 560 Ti SLI and single GK104.

Getting the FPS up to 45 made the games smooth in both setups. It terms of smoothness and stutter between SLI and single GPU setups, FPS was the only limiting factor to me.

The only issue I had with SLI / Xfire was that none of the MMOs I played supported it. DDO maxed out with 8x AA was dipping to around 30 FPS on SLI 560 tis, and the same with a single 560 ti. I had the exact same happening currently in Path of Exile, the 560 Ti config with one or two cards could not stay above 30 FPS because SLI wasnt working (I still have my 560 Tis and was using them when my 670 broke). On the other hand the 670 / 680 cards bring me up to 60-100+ FPS in those games at maxed settings, so for this reason I'm not bothering with SLI or Xfire again.

The way I noticed low FPS stuttering on my 680 was by using video capture locked to 35 FPS. I then tried 40 FPS and while a bit better, it was still stuttering. Locking it to 45 FPS made the stutter go away, but it was unrecordable without frame skipping too much over 35 FPS. Exactly the same results as my past SLI / Xfire setups.

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Originally Posted by boxleitnerb

You don't speak for everyone and you cannot possibly define what is generally noticeable and what is not.

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It isn't me who is defining "noticeable". Read any article or scientific paper about perceptive latency and you'll likely come to the same conclusion.

When I make a statement, don't think for a second that I haven't researched it to an extensive degree.

Links to some of said papers:

http://www.stuartcheshire.org/papers/LatencyQuest.html

http://www.ncbi.nlm.nih.gov/pubmed/16639613 (link to PDF @ source)

http://www.perceptionweb.com/abstract.cgi?id=p240749

If you have an account @ Sciverse / Science Direct, there are several other articles in their archives which discuss the same thing. Unfortunately, I can't post links to them due to copyright terms but you'll quickly get the idea after Googling a bit.

However, I will distill it down into plain speak: In extensive lab tests with and without human subjects, a time of 48 frames per second (ie: 20.83ms) was deemed to be the threshold at which the majority of people anbd test instruments saw completely smooth display images or refreshes.

One test actually went so far as to rapidly flash a lightbulb at variable speeds in order to demonstrate when people would see it "flicker". That threshold for 95% of the participants was at 50 flashes per second (ie: exactly 20ms).

Not sure how much more information anyone could be looking for here.... ;)

That explains why anything below 45 FPS was stuttering to me.

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Originally Posted by bhavv

That explains why anything below 45 FPS was stuttering to me.

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Precisely.

In addition, I think there has to be a distinction made between the continual stutter typically seen in multi GPU setups and individual frame stutter.

Continual stutter (also called micro stutter) is cyclical in nature and continues throughout a given sequence or section of a game, often repeating itself at regular intervals. For example, it would look something like this on a frame by frame basis: 10ms, 35ms, 10ms, 35ms, 10ms and so on. You would "see" the stutter every time a frame hit the 35ms mark. It would be seen like this:

http://images.hardwarecanucks.com/im...X-TITAN-88.jpg

Individual frame stutter meanwhile would point to instances where certain frames take an abnormally long time to render. It would look something like this: 10ms, 15ms, 12ms, 100ms, 10ms, 15ms, 11ms, 20ms, 18ms, 70ms. Here's an example of that:

http://images.hardwarecanucks.com/im...X-TITAN-87.jpg

Basically these many not be two completely separate phenomenons but they will read differently when viewed onscreen.

I don't agree with your claims SkyMTL. If microstutter below 20ms was unnoticeable as you claim how would people even benefit from a 120hz display? By those standards the difference between 60 and 90hz shouldn't be noticeable either.

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Originally Posted by BababooeyHTJ

I don't agree with your claims SkyMTL. If microstutter below 20ms was unnoticeable as you claim how would people even benefit from a 120hz display? By those standards the difference between 60 and 90hz shouldn't be noticeable either.

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You are confusing onscreen refresh rate and response times with processed frame times.

For example, the move from 60Hz to 120Hz isn't about eliminating flickering. Do you see less flicker on a 120Hz screen? Of course not. Rather it is about being able to drive a display ABOVE the 60 FPS mark with v-sync on. That leads to less input latency.

In addition, people don't buy 120Hz screens to eliminate microstutter. Indeed, a 120Hz screen won't do anything to eliminate microstutter if it is already being displayed due to above-20ms frame times.

Now, before you go and claim that's the same thing, it isn't.

First and foremost, quicker refresh rates all but eliminate the ghosting and input latency that occurs on lower-frequency LCD displays. Neither of those things is tied to GPU microstutter.

With that in mind, the difference between 90Hz and 60Hz will be noticeable on the INPUT side rather than on the overly VISUAL side (other than the ghosting of course).

Finally, they aren't claims. Perceptual latency detection above and below 48 FPS has a ton of science backing it up, much of which was sponsored by major production studios.

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Originally Posted by SKYMTL

It isn't me who is defining "noticeable". Read any article or scientific paper about perceptive latency and you'll likely come to the same conclusion.

When I make a statement, don't think for a second that I haven't researched it to an extensive degree.

Links to some of said papers:

http://www.stuartcheshire.org/papers/LatencyQuest.html

http://www.ncbi.nlm.nih.gov/pubmed/16639613 (link to PDF @ source)

http://www.perceptionweb.com/abstract.cgi?id=p240749

If you have an account @ Sciverse / Science Direct, there are several other articles in their archives which discuss the same thing. Unfortunately, I can't post links to them due to copyright terms but you'll quickly get the idea after Googling a bit.

However, I will distill it down into plain speak: In extensive lab tests with and without human subjects, a time of 48 frames per second (ie: 20.83ms) was deemed to be the threshold at which the majority of people anbd test instruments saw completely smooth display images or refreshes.

One test actually went so far as to rapidly flash a lightbulb at variable speeds in order to demonstrate when people would see it "flicker". That threshold for 95% of the participants was at 50 flashes per second (ie: exactly 20ms).

Not sure how much more information anyone could be looking for here.... ;)

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First, you absolutely cannot compare gameplay with just displayed sequences. 48 fps, is way too low for many games, think input lag. In some game engines, 100+ fps are required for truly direct control. Secondly, it is unimportant what the "majority" feels as long as there are still people who have higher standards.
So did you actually experience SLI/CF first hand or did you not? Theory has its place, but real life can be something different altogether. This smells like sugarcoating the problems that CF has. I'm always highly suspicious if some people - especially reviewers who should be objective and very careful with such stuff - tell me what I should or shouldn't be able to feel.

Sheesh. I spent the day with my finger hovering over the "buy" button on a second 7970 so I could look into this.

I have my doubts that a 7970 CF truly feels no faster than a single, and I'd like to put it to the test.

Not to mention I want Crysis 3 and Bioshock Infinite more than any games out right now. I've been having a lot of fun playing Sleeping Dogs and Far Cry3 from the first bundle, AMD is really hitting on all cylinders with their games included.

My 4870x2 always gamed fine, unless I pushed it to a point where it was VRAM, compute, or game engine limted. So far my SLI 670's have actually given me more trouble than that card ever did with respect to performance in either windowed or 1200p..

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Originally Posted by SKYMTL

You are confusing onscreen refresh rate and response times with processed frame times.

For example, the move from 60Hz to 120Hz isn't about eliminating flickering. Do you see less flicker on a 120Hz screen? Of course not.

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This depends greatly on the viewing source. Sit in front of a 50-60Hz CRT and you'll notice flicker immediately. If not, then for sure in direct comparison to an LCD or when you increase the refresh rate of the CRT to 75Hz for instance.

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Rather it is about being able to drive a display ABOVE the 60 FPS mark with v-sync on. That leads to less input latency.
First and foremost, quicker refresh rates all but eliminate the ghosting and input latency that occurs on lower-frequency LCD displays.

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Higher than 60Hz refresh rate isn't essential for minimizing ghosting on LCD screens. I use EIZO Colorgraphic monitors for video work, etc., the ghosting on them is basically non-existent. No consumer grade TN 120Hz or 144Hz comes even close to them in that respect. However, due to the display and hold nature of LCD screens, there's a significant difference in motion perception. This is directly related to the human visual system. The display itself plays a comparatively minor role in the perceived motion blur.

Fast paced gaming without VSync on a high refresh rate LCD also greatly helps to reduce tearing and/or the perception of it, which benefits tracking targets. It also reduces the hindrance of bright muzzle flash. The latter can be very annoying when it tears on a 60Hz screen, to the extent of almost temporarily impairing vision.

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With that in mind, the difference between 90Hz and 60Hz will be noticeable on the INPUT side rather than on the overly VISUAL side (other than the ghosting of course).

Finally, they aren't claims. Perceptual latency detection above and below 48 FPS has a ton of science backing it up, much of which was sponsored by major production studios.

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Here's a simple test:
1) ensure you have an LCD monitor with PWM controlled brightness
2) ensure the back light burns continuously at 100% brightness

3) wave your hand with fingers spread wide in front of your screen at 100% brightness
4) repeat same test at ~50% brightness.

In test 4 the PWM controlled back light typically flickers at 180Hz. You should clearly see a strobe effect when observing your hand movement.

@box

100 FPS isn't going to do anything over 60 FPS on a normal 60 hz screen. If FPS is maintained at over 50 on a 60 hz, I don't believe that you or anyone else are going to be noticing any stutter.

The frame spiking with crossfire in these tests however is a seperate issue to FPS, you may very well notice stutter due to that happening, and im not sure how frame limiting works or if it can be forced to 60 without dipping straight down to 30 like normal vsync.

I've usually found that people complaining about SLI / Xfire and microstutter haven't even used the setup they complain about themselves, and when people do notice lag / stutter, in most cases this is caused by FPS spikes rapidly dropping down to a low number. This is easily measurable in some bechmarks which record the minimum FPS. Most likely case is if you are seeing sudden lag / stutter on any GPU set up, the FPS is dropping far below 30 when you see it.

You can't judge an SLI / Xfire setup either way until you've tried it. I've been through SLI Geforce 6800s, GTX 460, and 560 Tis, and Xfire 3850s, 4850s, 4870s, 5770s and none of them were worse to me than a single card setup. I noticed the exact same lag and smoothness at the same FPS points, and I have perfect vision.

Looks like nvidia are just delaying one cards frame output by 10ms, whilst AMD are spitting out frames almost in unison. I'm not entirely sure how a monitor would react to that. Would it even show two frames rendered that close together? Would a buffered frame be shown in the gap between frame output?

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Originally Posted by Iconyu

Looks like nvidia are just delaying one cards frame output by 10ms, whilst AMD are spitting out frames almost in unison. I'm not entirely sure how a monitor would react to that. Would it even show two frames rendered that close together? Would a buffered frame be shown in the gap between frame output?

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Most monitor have so much time latency input, i dont think we can really see it...

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Originally Posted by STEvil

My 4870x2 always gamed fine, unless I pushed it to a point where it was VRAM, compute, or game engine limted. So far my SLI 670's have actually given me more trouble than that card ever did with respect to performance in either windowed or 1200p..

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4870x2 was a nice card in theory but it came with alot of cons and turned me off pc gaming cards along with the 4890 when I tried to trifire them.

I thought the card would have provided good value as it was cheaper than the pair of single cards and also had the larger memory configuration.

But the 4870x2 was as loud and hot as they get. The noise in particular was a high pitched fan noise with coil wine, it also didn't provide enough speed to maximize crysis. This experienced caused a chain reaction which would turn me off pc gaming in general with desktop cards.

Basically because of the noise and performance I got water blocks and a 4890 and I thought this would solve everything or so i thought. The trifire experience was awful after I installed the 4890. Couldn't even start my games even as the menu's to the games were all messed up. E.g I would have partial black screen with the menu shrunk on to the main screen, but I couldn't click the buttons in the menu to even start the game. I waited forever for AMD to fix this but they never did and with the 4890, the noise was even more outrageous. So basically I was stuck playing a single 4870x2 that was too hot and loud to tolerate(I don't wear headphones). AND the water blocks never got installed because I wanted to do it all at once to get the loop all set up but because of the aweful trifire experience I never ended up doing it. So two water blocks and a 4890, completely useless and a generally annoying 4870x2.

After spending this 1000 dollars and having that negative experience, I stuck with console's just because of all the hassle. It turned me off AMD cards and I made certain if I ever got a desktop card again, it would be a Nvidia card because of the unacceptable wait time for the fix.

The only thing that worked as it should have was 3dmark.

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Originally Posted by bhavv

@box

100 FPS isn't going to do anything over 60 FPS on a normal 60 hz screen. If FPS is maintained at over 50 on a 60 hz, I don't believe that you or anyone else are going to be noticing any stutter.

The frame spiking with crossfire in these tests however is a seperate issue to FPS, you may very well notice stutter due to that happening, and im not sure how frame limiting works or if it can be forced to 60 without dipping straight down to 30 like normal vsync.

I've usually found that people complaining about SLI / Xfire and microstutter haven't even used the setup they complain about themselves, and when people do notice lag / stutter, in most cases this is caused by FPS spikes rapidly dropping down to a low number. This is easily measurable in some bechmarks which record the minimum FPS. Most likely case is if you are seeing sudden lag / stutter on any GPU set up, the FPS is dropping far below 30 when you see it.

You can't judge an SLI / Xfire setup either way until you've tried it. I've been through SLI Geforce 6800s, GTX 460, and 560 Tis, and Xfire 3850s, 4850s, 4870s, 5770s and none of them were worse to me than a single card setup. I noticed the exact same lag and smoothness at the same FPS points, and I have perfect vision.

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I referred to input lag, not stutter. 100 fps will have lower input lag than 60 fps.

I'm curious what fps you were getting with your SLI and CF setups. If they are too low, microstutter will be worse. I cannot imagine gaming at 30-50 fps with SLI/CF, that is microstutter hell in most games. In some titles, even 60-80 fps are not smooth, for example I have experienced this in Serious Sam 3. Or look at PCGHs Ares Quadfire video. A whooping 70 fps in 3DMark11 and yet terrible stutter.

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Originally Posted by boxleitnerb

I referred to input lag, not stutter. 100 fps will have lower input lag than 60 fps.

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Could you explain how would this work ?I cant see any reason why higher amount of generated frames from gpu would lower input lag of a display when the synchronization remains at 60hz.Its interesting to me because im looking at monitors to buy atm however im not seeing any high resolution/high quality displays with low input lag.
My understanding is that input lag is introduced when display analyses and does some work on the frames got from gfx card before displaying it.To be honest i dont even see why input lag would get lower in 120hz display at 120fps.Its all about monitor electronics/display technology.

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Originally Posted by boxleitnerb

First, you absolutely cannot compare gameplay with just displayed sequences. 48 fps, is way too low for many games, think input lag. In some game engines, 100+ fps are required for truly direct control. Secondly, it is unimportant what the "majority" feels as long as there are still people who have higher standards.
So did you actually experience SLI/CF first hand or did you not? Theory has its place, but real life can be something different altogether. This smells like sugarcoating the problems that CF has. I'm always highly suspicious if some people - especially reviewers who should be objective and very careful with such stuff - tell me what I should or shouldn't be able to feel.

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You are correct. But we are not talking about input lag here. We're talking about motion fluidity. Basically, you can have completely fluid onscreen sequences but still experience input lag. :)

Under no circumstance should AMD's issues here be sugar coated and yes, they do have MAJOR issues. However, my intent was to inject some understanding of perspective versus the results being discussed here. While some sequences look quite bad, I maintain the differences will be so minor in actual gameplay, they'll be all but ignored by gamers (I'm talking sub-20ms frame times here by the way). Others which tend to spaz between two higher frame time points will of course be extremely noticeable.

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Originally Posted by SKYMTL

You are correct. But we are not talking about input lag here. We're talking about motion fluidity. Basically, you can have completely fluid onscreen sequences but still experience input lag. :)

Under no circumstance should AMD's issues here be sugar coated and yes, they do have MAJOR issues. However, my intent was to inject some understanding of perspective versus the results being discussed here. While some sequences look quite bad, I maintain the differences will be so minor in actual gameplay, they'll be all but ignored by gamers (I'm talking sub-20ms frame times here by the way). Others which tend to spaz between two higher frame time points will of course be extremely noticeable.

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The whole isue, and the fantastic Never Settle Reloaded bundle, intrigued me enough to order another HD7970 DD edition this morning.

I want to see for myself what all the reviews, posts are about. I've got a GTX680SLi rig powered by a now stock 990X, and now I'll have a 7970 CF rig powered by a stock 2500K. Both are equipped with Dell 25X16 monitors, rigs should be close enough I don't have to worry about differences too much, and if I see a big difference with SLi or CF being better I'll try swapping cards.

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Originally Posted by SKYMTL

You are confusing onscreen refresh rate and response times with processed frame times.

For example, the move from 60Hz to 120Hz isn't about eliminating flickering. Do you see less flicker on a 120Hz screen? Of course not. Rather it is about being able to drive a display ABOVE the 60 FPS mark with v-sync on. That leads to less input latency.

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No, the move to a higher refresh rate is for a smoother image in motion. Go check the display section at any popular forum and that'll be the general consensus. The difference in input lag between a 60 and 120hz display is not noticeable. In fact there are several 120hz displays with higher input lag than most 60hz displays.

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In addition, people don't buy 120Hz screens to eliminate microstutter. Indeed, a 120Hz screen won't do anything to eliminate microstutter if it is already being displayed due to above-20ms frame times.

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I didn't claim that it did. I did claim that you can see a difference in smoothness past 20ms.

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Finally, they aren't claims. Perceptual latency detection above and below 48 FPS has a ton of science backing it up, much of which was sponsored by major production studios.

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Yeah, whatever you say. There are a lot of people who would disagree with that. You can skew results to come out any way that you like it.

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Originally Posted by SKYMTL

I maintain the differences will be so minor in actual gameplay

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I disagree with your opinion.

I'll tell you right now, if it weren't for the ability to set up a framerate cap I would have sold my 7950s long ago.

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Originally Posted by STEvil

My 4870x2 always gamed fine, unless I pushed it to a point where it was VRAM, compute, or game engine limted. So far my SLI 670's have actually given me more trouble than that card ever did with respect to performance in either windowed or 1200p..

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I know in Crysis at 1920x1200 my 4870x2 didn't feel any smoother than my GTX280 despite the supposedly higher framerates. In general thats what I noticed with demanding games. That combined with poor performance in a few games like darkplaces and my modded morrowind install and off it went.

you are all forgeting about capabilities of panel itself. Sure, you may have 6ms on ips or 2ms on TN but that is gray-to-gray. blu-to-blue is more like 30ms, so BtB cannot achieve even 50fps, so in 120hz (120fps) BtB will be lagging behind GtG anyway. My point is - LCD panels are not capable of true 120hz/fps anyway. Don't get to exited.

edit: example: 3D crosstalk. Putting 500Hz refresh rate on a panel that is capable of displaying (all color transitions with all pixels firing up and down (on/off) ) some 80-90 fps will not yield a 500fp capability nor will it grant you a better experience than sam panel used in 120Hz monitor/TV. But hey, it would sell and placebo would rule the forums.
600Hz plasma anyone?

I have 2 MSI 7970 Lightnings with 3 of the new Asus VG248QE 144Hz 1ms monitors and I don't notice this microstutter everyone talks about. Maybe I'm just not sensitive to it...Which might be a good thing....

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Originally Posted by BababooeyHTJ

No, the move to a higher refresh rate is for a smoother image in motion. Go check the display section at any popular forum and that'll be the general consensus. The difference in input lag between a 60 and 120hz display is not noticeable. In fact there are several 120hz displays with higher input lag than most 60hz displays.

I didn't claim that it did. I did claim that you can see a difference in smoothness past 20ms.

Yeah, whatever you say. There are a lot of people who would disagree with that. You can skew results to come out any way that you like it.

I disagree with your opinion.

I'll tell you right now, if it weren't for the ability to set up a framerate cap I would have sold my 7950s long ago.

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I understand your opinions but I do highly recommend you read the science behind it before leaning towards a possible placebo effect.

Science to back up BababooeyHTJ motion claims:

http://scien.stanford.edu/pages/labs...Verslegers.htm

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Originally Posted by SKYMTL

I understand your opinions but I do highly recommend you read the science behind it before leaning towards a possible placebo effect.

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You didn't link anything to prove your point on the subject. Just because you don't notice a difference doesn't mean that many other people don't.

I know what I've seen and I don't know many gamers with a fair amount of experience with a 120hz display that don't notice smoother motion at a higher refresh rate.

There are a lot of people who don't notice the 64hz bug in Oblivion, Fallout 3, and new vegas despite it being there in every 60hz display. Now that I think about I've never seen you mention it either.

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Originally Posted by cx-ray

Science to back up BababooeyHTJ motion claims:

http://scien.stanford.edu/pages/labs...Verslegers.htm

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That's motion blur. Not stuttering or (in HDTV terms) judder. ;)

Remember, when V-Sync is turned OFF, frame times and frame rates run asynchronously to refresh rate.

But now, we're straying pretty far afield since the refresh rate discussion only comes into play when comparing noticeable flickering (at sub-48Hz to 50Hz intervals) with my statements previously about frame intervals of 20.83ms.

I've only used crossfire my self, I've never noticed any kind of stuttering.

Aren't they using AFR (alternate frame rending) to render now ?

I recall, way back in the 3,000 series there was option to change the rendering type

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Originally Posted by demonkevy666

I've only used crossfire my self, I've never noticed any kind of stuttering.

Aren't they using AFR (alternate frame rending) to render now ?

I recall, way back in the 3,000 series there was option to change the rendering type

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They used to offer tiled rendering and half-screen rendering, but I believe there were often driver issues and image quality problems when combining the two images, especially in tiled mode.

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Originally Posted by [XC] Lead Head

They used to offer tiled rendering and half-screen rendering, but I believe there were often driver issues and image quality problems when combining the two images, especially in tiled mode.

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it's an OLD can of worms. :|

http://techreport.com/review/14284/c...e-x-explored/2

This test makes absolutely no sense at all. You don't want to know the value of the average 99% of the frames. It's that 1% of slow frames that destroy the experience.
What I want to know is which card has the minor slow frames, and which one renders them fastest.

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Originally Posted by SKYMTL

That's motion blur. Not stuttering or (in HDTV terms) judder. ;)

Remember, when V-Sync is turned OFF, frame times and frame rates run asynchronously to refresh rate.

But now, we're straying pretty far afield since the refresh rate discussion only comes into play when comparing noticeable flickering (at sub-48Hz to 50Hz intervals) with my statements previously about frame intervals of 20.83ms.

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The examples in my two posts of this thread were to illustrate that we can observe differences in motion far beyond the 48 FPS that you state. It may not be apparent when just viewing a single source. In direct comparison however, differences are quite easily detected. You don't have to be a picky or sensitive person for that.

You guys are mixing two things up. Input refresh frequency doesn't have to be the same as display or frame drawing frequency. I think Doom 3 was the first to start that trend - it had 60 Hz on input even when fps was lower.

Other games have those two connected - Quake 3 for example. If you had fast enough PC back in the day, and good enough monitor, you could have easily sensed the difference in input when 'overclocking' ps/2 sampling rate.

I got my 7970CF rig running last night, intel 990X CPU, 3X2GB Patriot RAM, old school 7200RPM 1TB drive, Dell 3008 25X16 display.

I played some Crysis 3 at everything on very high, 4XMSAA 16XAF. It was pretty sluggish, but with CF off, it was MUCH worse. So I think I established a baseline of info that at settings one 7970 can't handle, adding a second doesn't "play the same due to short rendered frames" at Crysis 3 anyway. I'll see if I can find settings where the 7970 can mostly handle the game, and whether turning on CF improves/detracts from it in any way as perhaps the impact of the measured short frames is more subtle. (like 60fps feels the same as 40fps so you're not really getting any benefit from the second card)

Then I switched the settings to everything on high but shadows on low, water on medium, and 2X SMAA, 16X AF and used CF a good while. (which I thought might be similar to what I was doing with my 680 SLi , FXAA+16X AF) Gameplay was very smooth and enjoyable, didn't notice any game altering microstutter.

I realize these results aren't scientific, only observed, but I'm going to leave the 7970s in my main rig for a while and play a variety of games and see if I notice any hitching or fluctuations in fluidity with the CF.

Imo the sad thing is crysis 3 IQ barely changes when you lower certain graphics options and you get much better performance.

Played UT3, Sleeping Dogs, and Max Payne 3 tonight. All seemed to run smooth to me.

UT3 had some random weird flashes when I forced AA on it.

My installs of UT2004 and Metro 2033 didn't work at all. The former because my 25X16 hack wouldn't display, the latter trying to load a PhysX DLL. My guess is I wouldn't have problems with either if I had set them up with AMD to start.

All in all I have to say I'm pretty happy with the 7970CF. I don't doubt these review sites results, but am starting to think they're not *"WTF is this crap" dealbreakers.

Definitely a place in my world for CF with these bundles. Probably not as good as 680 SLi all the way around, but for $100 less and 5 great games, a strong contender.

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Originally Posted by rk7p5

Imo the sad thing is crysis 3 IQ barely changes when you lower certain graphics options and you get much better performance.

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This.

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Originally Posted by boxleitnerb

First, you absolutely cannot compare gameplay with just displayed sequences. 48 fps, is way too low for many games, think input lag. In some game engines, 100+ fps are required for truly direct control. Secondly, it is unimportant what the "majority" feels as long as there are still people who have higher standards.
So did you actually experience SLI/CF first hand or did you not? Theory has its place, but real life can be something different altogether. This smells like sugarcoating the problems that CF has. I'm always highly suspicious if some people - especially reviewers who should be objective and very careful with such stuff - tell me what I should or shouldn't be able to feel.

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What? Some engines require 100+ fps because the fps is tied to the control and other things. So, more fps = the game runs different. This has nothing to do with visuals... for instance, in many Quake games fps has a great effect on how the player moves around the scenario.

48fps, by the way, is not slow by any means. The problem is that FPS is not an even stream of data, and the more fps you have, the more close to each other they are and, thus, the smoother the experience is. For instance, the Crysis titles are far more playable at 40-50fps than most of the games out there, and its precisely because their engine works in a different way and doesn't spike as others do.

Also... SKYMTL is part of hardwarecanucks (not sure if the owner/main editor/just another crew member). So, it's safe to assume he has tinkered with more SLI and CF than most of us ;)

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Originally Posted by cx-ray

This depends greatly on the viewing source. Sit in front of a 50-60Hz CRT and you'll notice flicker immediately. If not, then for sure in direct comparison to an LCD or when you increase the refresh rate of the CRT to 75Hz for instance.

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This has nothing to do with the issue. A CRT is unable to have a static image on it. It simply can't, and thus the flickering. Flicker is simply part of the CRT, and having a higher refresh rate only mitigates it, but it still there.

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Higher than 60Hz refresh rate isn't essential for minimizing ghosting on LCD screens. I use EIZO Colorgraphic monitors for video work, etc., the ghosting on them is basically non-existent. No consumer grade TN 120Hz or 144Hz comes even close to them in that respect. However, due to the display and hold nature of LCD screens, there's a significant difference in motion perception. This is directly related to the human visual system. The display itself plays a comparatively minor role in the perceived motion blur.

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The new 3D Vision 2 monitors have close to non crosstalk, which means that their ghosting is effectively 0.

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Originally Posted by bhavv

@box

100 FPS isn't going to do anything over 60 FPS on a normal 60 hz screen. If FPS is maintained at over 50 on a 60 hz, I don't believe that you or anyone else are going to be noticing any stutter.

The frame spiking with crossfire in these tests however is a seperate issue to FPS, you may very well notice stutter due to that happening, and im not sure how frame limiting works or if it can be forced to 60 without dipping straight down to 30 like normal vsync.

I've usually found that people complaining about SLI / Xfire and microstutter haven't even used the setup they complain about themselves, and when people do notice lag / stutter, in most cases this is caused by FPS spikes rapidly dropping down to a low number. This is easily measurable in some bechmarks which record the minimum FPS. Most likely case is if you are seeing sudden lag / stutter on any GPU set up, the FPS is dropping far below 30 when you see it.

You can't judge an SLI / Xfire setup either way until you've tried it. I've been through SLI Geforce 6800s, GTX 460, and 560 Tis, and Xfire 3850s, 4850s, 4870s, 5770s and none of them were worse to me than a single card setup. I noticed the exact same lag and smoothness at the same FPS points, and I have perfect vision.

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Oh, it does. You consider framerate as a steady stream of frames, when it isn't. With 100fps you have far higher chances of never skipping a frame than with 60fps (@60hz screen). So, the bigger the number, the better.... and stuttering is not only related to multi-gpu setups, as it exists on both systems (single and multi-gpu).

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Originally Posted by vario

Could you explain how would this work ?I cant see any reason why higher amount of generated frames from gpu would lower input lag of a display when the synchronization remains at 60hz.Its interesting to me because im looking at monitors to buy atm however im not seeing any high resolution/high quality displays with low input lag.
My understanding is that input lag is introduced when display analyses and does some work on the frames got from gfx card before displaying it.To be honest i dont even see why input lag would get lower in 120hz display at 120fps.Its all about monitor electronics/display technology.

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Only if you have Vsync on. Tearing happens precisely because you are drawing different frames at once. This is pita, but at the same time you have your lastest inputs drawed into the screen. Food for thought...

About input lag, the higher the refresh rate, the lower the input lag (provided the pannels are as fast). Why? Whenever you input something into your computer, it will take a time to get pictured on screen. The fact that at 120hz you update your computer twice as fast means that the time between input and picture will also be lower. Think about it this way: you are expecting a package, and you can choose between a company that makes 1 delivery per day or another that makes 5 deliveries per day. Which one will give you your packet faster, provided you don't know when the packet will reach the office? It's kinda simple actually...

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Originally Posted by gx-x

you are all forgeting about capabilities of panel itself. Sure, you may have 6ms on ips or 2ms on TN but that is gray-to-gray. blu-to-blue is more like 30ms, so BtB cannot achieve even 50fps, so in 120hz (120fps) BtB will be lagging behind GtG anyway. My point is - LCD panels are not capable of true 120hz/fps anyway. Don't get to exited.

edit: example: 3D crosstalk. Putting 500Hz refresh rate on a panel that is capable of displaying (all color transitions with all pixels firing up and down (on/off) ) some 80-90 fps will not yield a 500fp capability nor will it grant you a better experience than sam panel used in 120Hz monitor/TV. But hey, it would sell and placebo would rule the forums.
600Hz plasma anyone?

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Oh, you are wrong. The new 3D pannels have no cross-talk... meaning: no ghosting whatsoever, and cross-talk is by far the hardest test of them all, as they are drawing 2 different frames one after another, and if anything gets mixed into them they eliminated the blurr altogether.

http://www.youtube.com/watch?feature...&v=hD5gjAs1A2s

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Originally Posted by prava

This has nothing to do with the issue. A CRT is unable to have a static image on it. It simply can't, and thus the flickering. Flicker is simply part of the CRT, and having a higher refresh rate only mitigates it, but it still there.

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My/our replies were part of an ongoing discussion over several directly and or loosely related subjects. You may have missed the context of what was written.

The above was in response to what was mentioned here:

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One test actually went so far as to rapidly flash a lightbulb at variable speeds in order to demonstrate when people would see it "flicker". That threshold for 95% of the participants was at 50 flashes per second (ie: exactly 20ms).

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Originally Posted by prava

The new 3D Vision 2 monitors have close to non crosstalk, which means that their ghosting is effectively 0.

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Those issues aren't directly related. I have an XL2420T 3D Vision 2 monitor. It has ghosting due to overdrive overshooting artifacts. I only use that monitor for high refresh rate 2D gaming. It's not bad enough there to be of a concern to me.

Played Far Cry 3 at 2X and 4X MSAA override tonight, CFx was a mess. Disabled it actually played better. Don't know if this is Windows 8 specific or just bad CFx, but it was really stuttering.

Got tired of that and played UT3 for half an hour at 2X MSAA override. It played really well till it crashed.

I'm starting to think CFx is a little dodgy, not as seamless as SLi. (although I wonder if being on Windows 8 may be playing a part)

I've had some games work great, one work like crap, one flash and crash, one not run with a modified ini & cfg that worked with SLi, and one not run due to something with PhysX DLL.

Thats true, crossfire isn't as good as sli. I don't think that anyone can argue that.

I hear far cry 3 is bad in both sli and crossfire. I wouldn't go testing hardware on that title.

I had to cap my framerate in most titles for a truly smooth experience.

I would definitely consider Win8 to be a possible problem. I've tried it, didn't like it, thought maybe I needed to give it more of a chance, started having issues in games, reverted back to Win7, issues went away. Not interested in Win8 until at least SP1 but... probably not even then. Too many clicks now to do the same thing as Win7.

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Originally Posted by Rollo

Played Far Cry 3 at 2X and 4X MSAA override tonight, CFx was a mess. Disabled it actually played better. Don't know if this is Windows 8 specific or just bad CFx, but it was really stuttering.

Got tired of that and played UT3 for half an hour at 2X MSAA override. It played really well till it crashed.

I'm starting to think CFx is a little dodgy, not as seamless as SLi. (although I wonder if being on Windows 8 may be playing a part)

I've had some games work great, one work like crap, one flash and crash, one not run with a modified ini & cfg that worked with SLi, and one not run due to something with PhysX DLL.

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No, microstutter has been an issue that AMD has never properly addressed. Its not as bad as the 4870x2 but still an issue. I noticed it in quite a few games in windows 7 with a pair of 7950s and even 7950 tri-fire. Yeah, tri-fire doesn't really help with microstutter from what I've seen. I always wondered about that and is a big part of the reason that I picked up that third card. Yeah, it didn't help. Scaled well though.

I wouldn't be surprised if Windows 8 had more issues. I regretted moving to windows 7 from Vista those first few months. Mostly due to Nv drivers at the time.

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Originally Posted by prava

Oh, you are wrong. The new 3D pannels have no cross-talk... meaning: no ghosting whatsoever, and cross-talk is by far the hardest test of them all, as they are drawing 2 different frames one after another, and if anything gets mixed into them they eliminated the blurr altogether.

http://www.youtube.com/watch?feature=player_embedded&v=hD5gjAs1A2s

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Lightboost does not eliminate crosstalk, it just reduces the visual effect of it (which is fine, but only part of the fix to the issue). Also ghosting is not caused by only crosstalk, it is also (and primarily) caused by pixel excite/decay rates (GtG for example).