yeah i've been getting the same problem with UT2004 demo, as well as a variety of other game demos for OSX, like COD2, and Halo1 demo. bottom line is they all run like crap, i.e. under 20fps, which is inexplicable by the hardware that we're running them on. i read somewehre it's because the demo versions are not universal binary? but why not? if i was downloading them witht he intention of buying the game in the end, i certainly wouldn't buy it after getting performance like that.. so why wouldn't they make the demo representative of what you'd actually get....??? doesn't that make more sense?
it's kind of reassuring that the fps difference goes from 20 on lowest settings to about 10-15 on highest settings with all the games... so i was quite sure it wasn't to do with the machine... because of the inproportionate difference in performance