http://www.elderscrolls.com/games/oblivion_faq.htm
Recommended:
3 Ghz Intel Pentium 4 or equivalent processor
1 GB System RAM
ATI X800 series, Nvidia GeForce 6800 series, or higher video card
Minimum System Requirements:
Windows XP
512MB System RAM
2 Ghz Intel Pentium 4 or equivalent processor
128MB Direct3D compatible video card
and DirectX 9.0 compatible driver;
8x DVD-ROM drive
4.6 GB free hard disk space
DirectX 9.0c (included)
DirectX 8.1 compatible sound card
Keyboard, Mouse
Sweet fancy Moses!