I have played ut04 with 12 bots, and the map with a lot of veichles (where you have to get all the bases, so you can destroy the powernode) for about 2 hours, and it doesn't get near as hot as when playing far cry.
Have you tried the far cry demo? Because if you haven't, try it and see for yourself.
The game has very nice graphics, much better than any unreal game out there.