Frame pacing causing stuttering and clock fluctuations on 295x2

[nails666]

I've noticed some odd behaviour recently on my 295x2 and I've been able to pin it down to the Frame Pacing option in CCC.
I know in theory that when enabled it's supposed to help smooth out the frame times when running in XFire but for me it seems to have the opposite effect.
In the Heaven benchmark I've always been able to see a slight judder roughly every second even when running with Freesync enabled and it's always really annoyed me so I was fiddling with settings to try and remove and sure enough if I turn Frame Pacing off the judder goes away and it's all perfectly smooth. While the Witcher 3 isn't a great example as it tends to stutter in XFire anyway I've again found that turning Frame Pacing off does noticably improve the smoothness as well.
The other thing I've noticed is that for quite a few driver versions now (I'm currently running the latest 15.10 betas) the core clocks of both gpus would fluctuate constantly when gaming. The fluctuations aren't massive, between 950 - 1018MHz, but they occur all the time even when the temps are well below the throttling threshold and whatever game I'm playing isn't near the fps cap I've set (120fps at the moment). I've got the power limit set to +50% so it isn't that either. However now since I've switched off Frame Pacing my clocks have gone back to being stable at 1018MHz.

Has anyone else noticed any of these quirks when using Frame Pacing or is it just me?

 

[nails666]

Yeah it starts as soon as the game or bench begins when the temps are well down in the 60s.

 

[nails666]

Hi Matt, yeah I've seen that item on the patch notes but I've not got FRTC enabled. When I do set a cap I use MSI Afterburner but I get the same fluctuations even with no cap set.

 

[nails666]

Thanks. Can you drop me a trust message with your DXDIAG.TXT file so i can investigate and see if i can reproduce this?

Turning off frame pacing resolves the clock fluctuations? Does that apply to every game or just the ones mentioned?

Thanks Matt, I'll try and get some more details tonight if my 5 week old son sleeps long enough for me to get on the computer

 

[nails666]

Yup already tried that, I have it set to +50% in MSI Afterburner. Is there anyway to confirm that's definitely been applied?

 

[nails666]

Right, I've had a chance to run a few tests now on Heaven Bench, Witcher 3 and Crysis 3. All three show the same effect on clock speed from having Frame Pacing on and off although on Heaven the effect was very small.

Crysis 3 results: -

Spoiler

On here you can see the Afterburner logs of 2 runs from exactly the same save point. The first run with Frame Pacing on and the second with it off. You can see with it on the core clocks (3rd graph down) move a lot while with it off they are solid at 1020MHz.

Witcher 3 results: -

Spoiler

Same effect here as well and note that both gpu usage and fps here are higher with pacing turned off.

Heaven Bench results: -

Spoiler

On this one the pacing off is the first run and there are only a couple of little drops with it on.

I checked in CCC and my power limit is definitely set to +50%.

Spoiler

I'll send a trust with the dxdiag.txt to you shortly Matt.