Microstutter in latest-gen cards - examples included

[damha]

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!

[Arseface]

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

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):




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).

[Oztopher]

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

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.

[Carfax]

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



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.

[Arseface]

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.

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...

[Carfax]

... 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...

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

I'll run it again later and double check.

[damha]

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):




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

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

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.

Thanks

[Chickenfeed]

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.