The settings described here should provide maximum performance and stability:
UC or USWC - USWC. See 'I have a Video Memory option in my BIOS that I can set to UC or USWC. What should it be set to?' question.
Fast Writes - Enabled.
AGP Mode - 2x or 4x, depending on whether your motherboard supports AGP4X or not.
AGP Driving Control - Auto.
AGP Master 1 WS Write - Enabled.
AGP Master 1 WS Read - Enabled.
AGP Aperture - see 'What should my AGP Aperture size be set to?' question. Also, you may wish to read the 'How can I change my AGP Aperture size?' question.
Assign IRQ to VGA - Enabled.
Video BIOS Shadow - Disabled.
Video BIOS Cacheable - Disabled.
Video RAM Cacheable - Disabled.
C8000 - xxxxx Shadow - Disabled.
Peer Concurrency - Enabled.
Concurrent PCI Host - Enabled.
PCI Streaming - Enabled.
VGA Palette Snoop - Disabled.
You can also try these settings if you are having problems:
