Users running their PC in Dual Display configuration with a NVIDIA 6800 card will face low FPS and drops down to 3-4FPS in some areas of Doom III. But there’s a way to fix it.

We’ve discovered a driver bug with NVIDIAs current drivers v61.76/61x77 in Doom III (we did not test with older drivers yet). It causes a performance drops down to 3FPS in certain parts of a level and a lower overall FPS, when your GeForce 6800 is running with multiple displays in dual view mode - and only on systems running in dual display mode !! If you have only one display attached, everything should be fine ! We did not test yet if other cards are also affected.

If this happens, it can be fixed by setting the Hardware Acceleration mode from "Multi-display performance mode" (the default driver setting when dual display mode is used) to "Single Display Mode". You can find this in the "Performance & Quality" settings, under advanced settings.

The issue can be fixed by setting Hardware acceleration to Single Display Mode.

NVIDIA is investigating the issue and working on it.