I've recently upgraded my Windows 8.1 installation to Windows 10 (final build) and, of course, installed 15.7.1 drivers as the latest and only driver version supported on that OS. What I almost immediately noticed is that everything lost a few frames per second, but more importantly most of the titles started exhibiting fluctuating framerate. The behaviour is the same in every game I tested so far, but I'll give the example based on Witcher 3 (version 1.07), because it's most apparent there (probably because that is the game I'm currently playing on my PC).
After launching the game is working normally for about half an hour to 45 minutes. After that, framerate starts fluctuating, sometimes between 35 and 55, almost constantly. When I stand motionless in place, framerate remains unchanged, but any movement accross the scene immediately causes fluctuations. Stuttering also starts to show. And the same thing happens in Tomb Raider, Shadow Warrior (DX11 version, DX9 not tested) and Rocket League. Even benchmarks like Unigine Valley and Heaven or 3DMark exhibit this behaviour after a short while of looping. Once the thing starts happening, only a reboot fixes it. Restarting the application does not help, nor does running different one. The fluctuations intensify quickly over time, and after a few minutes everything is basically rendered unplayable, because framerate constantly drops, and stuttering increases, with more and more dropped frames.
I've monitored VRAM and RAM usage, found nothing out of the ordinary. There are also no spikes in CPU nor GPU usage. The issue did not manifest on 15.7 on Windows 8.1. I've double checked my PSU to make sure there was no "coincidental failure", but it seems to be fine, with all voltages at normal and reported currents the same as before update. The issue is independent vsync, FreeSync usage or graphics details the games are set to.
My specs are:
AMD Phenom X6 1100T @ 3,7/4,0Ghz
AMD Radeon R9 290 4GB (reference board, from ASUS)
ASUS M5A99X EVO R2.0 motherboard
If I could take a wild shot, I'd say there is a memory leak somewhere, because the framerate fluctuations are similar in nature to what my old 1GB Radeon 6870 was doing when it ran out of VRAM and had to swap to system memory. But that's just my guess, with nothing to back it up. Anyone else seeing similar issues and/or knows a possible fix?