In order for you to play DOOM 3 on Windows with minimal graphics settings, your computer must meet the following requirements
OS *:
Microsoft® Windows® 2000/XP (Does not support Windows Vista/7)
Processor (CPU):
Pentium®IV 1.5 GHz or Athlon® XP 1500+ processor or higher
Memory (RAM):
384 MB RAM
Graphics Card:
100% DirectX® 9.0b compatible 64MB Hardware Accelerated video card and the lateset drivers
DirectX®:
DirectX® 9.0b (included)
Hard Drive:
2.2GB of uncompressed free hard disk space (plus 400MB for Windows® swap file)
Sound:
100% DirectX® 9.0b compatible 16-bit sound card and the latest drivers
Multiplayer Requirements:
Internet (TCP/IP) and LAN (TCP/IP) play supported, Internet play requires broadband connection and latest drivers, LAN play requires network interface card and latest drivers
Supported Chipsets:
ATI® RadeonTM 8500, ATI® RadeonTM 9000, ATI® RadeonTM 9200, ATI® RadeonTM 9500, ATI® RadeonTM 9600, ATI® RadeonTM 9700, ATI® RadeonTM 9800, all nVidia® GeForceTM 3/Ti series, all nVidia® GeForceTM 4MX series, all nVidia® GeForceTM 4/Ti series, all nVidia® GeForceTM FX series, nVidia® GeForceTM 6800*Important Note: Some 3D accelerator cards with the chipset listed here may not be compatible with the 3D accelerator features utilized by Doom 3. Please refer to your hardware manufacturer for 100% DirectX 9.0b compatibility. This product does not support Microsoft® Windows® 95/98/ME or NT.