I seem to have no problems with my ASUS NVIDA GT 640 card.
Download the latest driver.
http://www.nvidia.com/Download/index.aspx?lang=en-us In the Control panel do following settings.
Manage 3D setting
Texture filtering - Quality = High quality
Power management mode = Prefer maximum performance
Ambient Occlusion = Performance
Antisotropic filtering = 16x or 8x
Antialiasing - FXAA = ON
Antialiasing - MODE = Override any application setting
Antialiasing - Setting = 16x or higher
Antialiasing - Transparency = 4x (supersampling) or higher
CUDA GPUs = All
Threaded Optimization = ON
Triple buffering = ON
Vertical Sync = ON
Configure Surround, PhysX It is very important that you set PhysX Processor to your Graphic card ony! In your case
Geforce GT 630. Not Auto select that are the default setting. Default setting make the card use the CPU too.
Adjust desktop color settings Change on every monitor that you use to---> = Use NVIDIA settings
Don't forget to do "Apply" when you are done.