So I looked around in the Catalyst Controll Center, but didn't find anything like that. I guess it's supossed to be ATI Overdrive, but that doesn't seem to work to me.So in Power Management I changed the settings from Balanced to Performance. Even disabled PCI Express in all my powersettings profiles just in chase. But still the CCC said my GPU was clocked at 240MHz. So I downloaded a small tool called GPU Tool. It let me manually change the voltage and clock speed.So I set it to 880 in 2d/low mode, meaning it should always be clocked at 880MHz, right?
Anyway, now I can't change any settings in CCC, however this isn't a big problem as I can use GPU-Tool for that now.But still, whenever I play Quake, it works fine for a while, then my FPS drops like hell.It's not capped at 30FPS any more, it goes all crazy all over the place.First it's stable 125 like it used to be, then it goes from 3-80 FPS, before it goes to 125 for a little while again, then down to 2-3 fps.I even tried setting all Quake 3 settings to the ultimate low, like pikmip 3 or whatever, and 640*480 resolution, just to test. It's still like 5 FPS.
The thing that pisses me off the most is that CCC still says there is 0% Activity on the GPU.

New screen:http://img704.imageshack.us/img704/1105/gputool.jpg

Okay, played some more now, still dropping FPS, but at least now the Activity in CCC is starting to move some.It goes from 3% to 7-8%. But it's still laggy as hell. So I'm guessing now it's more likely to be a CPU problem?