I can play the game on my mother's machine, but not this one. That means no internet play for me for a few months at least.
An Nvidia GeForce 3 graphics card or ATI Technologies 8500: Column author Dwight Silverman says that given the game's demanding visuals, serious gamers should splurge for a GPU from Nvidia's GeForce FX or 6800 line or ATI's Radeon 9800 or X800 series. He says more frugal PC owners can make do with a GeForce 5900XT or a Radeon 9600XT.
A 1.5-gigahertz Intel Pentium 4 chip or AMD Athlon 1500: Though these will run the game, Silverman suggests a 2GHz Pentium or equivalent, with the "ideal" processor being 3 GHz or over.
384MB of memory: Again, Silverman stresses that this is a minimum requirement, and he recommends 512MB at least, with 1GB preferred.
Two GB of hard drive space:. Four GB is suggested if your PC is running low on free space.
http://www.gamespot.com/pc/action/doom3/news_6103036.html