No discernible performance increase for me.
Temps went up approx. 5 Celsius...
Might as well keep'm...no apparent harm to anything.

For my GAINWARD GTX560 TI 2gb I use the following settings:

Anisotropic filtering == 16x

Antialiasing - FXAA == Off

Antialiasing -Setting == Application-controlled

Antialiasing - Gamma correction == Off

Antialiasing - Mode == Override any application setting

Anti-Aliasing - Transparency == 4x (Supersampling)

Power management mode == Prefer maximum performence

Maximum pre-rendered Frames == Use application setting

Multi-Display / mixed-GPU acceleration == Single display performence mode

Texture filtering - Anisotropic sample optimization == Off

Texture filtering - Negative LOD bias == Clamp

Texture filtering - Quality == Quality | High quality

Texture filtering - Trilinear optimization== Off

Threaded optimization == Auto

Vertical sync == Automatic (interval 2)

Regards Varrattu