The latest public version is 9.0c, also comes with SP2
Doom3 is likely to be a bit lagged with full AA, I think most things will be 🙂
As for the 3000, try new drivers.
I do have a different processor and I don't think RAM is an issue.
Even tho I am running a 64bit processor, I am still using a 32bit OS - even still it does have extra features that still work with 32bit os, that will give advantages.
Also even tho I stated I am at stock, I had Turbo mode enabled in my bios, seemed to make things run at a higher temp, so faster.
Also my POV card, as stock comes with 2D 400/1000 3D 415/1100
Also what is a slimline startup? I normally kill the odd service before I do mine.