I bought Doom 3 when it first came out. Played it to the end, even best the end.
I havent played it in a long time, and I removed it from my computer to save space.
But I remember that it needs a very powerful computer, lots of ram, and a high end video card.
Just found the box. Here are the minimum requirements:
Full version of Doom3
Win 2000 or XP
P4 1.5 gig or better
384 meg of ram (It work work good on this much though, I upgraded to a gig).
Direct X 9.0
3D hardware accelerator card. (It gives a list 9 cards on the box.)
Wait a minute, this is the expansion pack I bought after I beat the basic game, so Im not sure about the requirements for the actual game. (Cant find the original box.)
But I do remember that I had 512 meg ram and it was very choppy, until I doubled the ram.
The video card is critical too. it wont work on all cards.
I like Doom, I have been playing it since the first dos versions.
Have you tried Serious Sam? I think I like it better than Doom.
I have yet to finish the final level of Serious Sam, The Second Encounter.