all of it, TBH. Yo ucant upgrade one without another becoming bottleneck. That ram is horrid, its gonna give you lots of skipping so be on AT LEAST a gig.
That video card probably doesn't work to well in Doom 3 unless your run really low detail.
And the CPU, while ok, it also means you need to upgrade this if you get another video card or else it wont really work too good.
With that rig, how does Doom 3 play and on what settings? I'm guessing 20-30 FPS average on low/medium, possibly with shadows disabled?
Didn't bother with d3. I am willing to play at low as long as there is some intelligent opposition (online play). That's why I didn't get doom 3. You here all agreed it was horrid online. Quake 4 seems promising though.
I would suggest downloading the Doom 3 demo and giving it a go, just to stress test your system. You dont want to be caught with your pants down when Quake 4 hits and you cant even run the menu (like many did with Doom 3).
Survivor wrote:20 to 30 fps on both low without shadows and med with shadows. Seems reasonable to me. Never were many monster on-screen though.
I'd advise a totally new system, as Odium suggested. If you can't do that then at least get a new vid card (6600 is the best bang for buck right now, especially with OpenGL games).