"Low power" GPU mode

I recently bought a BFG GeForce 7800GSOC (after also buying a larger power supply) to replace my GeForce 6600, and at first had problems with low frame rates. Sometimes after clearing out some cache and reinstalling chipset drivers I thought I was out of the woods, but next time I started up my machine I had the same low framerates as before. It turns out there seems to be a problem with the 2D/Low Power mode switching - sometimes it would not switch to high power mode when playing games.

So if you ever run into this problem, simply get RivaTuner, go to the 'Power User' tab, go to 'RivaTuner \ NVIDIA \ Overclocking' and set EnablePerfLevelForcing to '1' and click Aply. Now go back to the Main tab, select Customize -> System Settings, and set 'Force constant performance level' to 'performance 3D'. It sounds like a lot of steps, but the first series is to simply enable the second.

I can now play Battlefield at 1600x1200 2xFSAA at decent fps with most everything on high. Although I still need to use medium texture - the GPU can handle high, but the disk access makes the game stutter until all the textures are loaded.