Terrible 7970M full screen performance on Windows 8.1

[Thorarin]

I have a M17x R4 with 7970M. Last week I upgraded to Windows 8.1. After the upgrade, I lost my dedicated graphics until I installed these drivers (AMD 13.151).

However, now I'm seeing a very strange performance issue. I was trying to play Rift on the laptop, but it was performing even worse than it was before I reinstalled the AMD drivers. I was getting about 2 FPS on settings that were previously fine for the laptop. After some experimentation I figured out that the performance is fine when I run the game in windowed mode, but it is terrible when running full screen.

I realize this is a pretty specific set of circumstances, but has anyone seen something similar, or does anyone have any suggestions on what I could try to resolve this?

[Senshin]

I have also some weird problems since on windows 8.1, i just gonna hold my breath for little while and hope everything will be fixed.

I think you just need to play windowed mode what i geuss ain't a big problem, or try other drivers becuase this is clearly a Video(card,driver) problem.

[Thorarin]

I will do the same for now. I had some issues doing a clean install last time I tried, so I'm not quite ready for that yet.

I'll try with some other games as well and see if they have similar issues.

[Thorarin]

I've just tried the same with Neverwinter, which was the only other game I have installed on the laptop. I get a similar performance drop when playing full screen, so for the time being I'll assume it's a fairly common driver issue and will be fixed in some later version.

[MrCat]

I upgraded to 8.1 had to format and reinstall 8, pretty much all my beloved games became unplayble due to windows 8.1 'mouse issues', clicking the left mouse button while holding a key (moving forward, ..) was impossible on 8.1!!