For comparison, I have:
Athlon 1.3GHz system,
512MB RAM,
ATI Radeon 7200 (very old)
I run in 800x600 window and get about 25-30FPS in Normal graphics mode. Fullscreen it is about the same.
So, no framerate problems here, although I have to say that UT2K4 framerate is not much worse than DOM2 but certainly is much nicer looking
But that is OK with me, I don't play DOM2 for the graphics. I mean I played tons of Stars!@# and that game had maybe the worst graphics of any game ever released since Zork.