As with many others on this site, I have been having problems with UT regarding the infamous "speedstep" functionality on Intel and AMD processors. I tried setting my power settings to "High Performance", and lo and behold, the game no longer stuttered between slowdown-speedup. Now, however, the game will just COMPLETELY slowdown after a few minutes of play. Thoughts?

Do you have a desktop PC or a notebook? If it's a notebook, perhaps you have some software installed which changes power management states, regardless of what you selected in your Control Panel... Hell, it might even manipulate the FSB or CPU multiplier by itself. :)

I think I have this problem licked. I set processor speed to 50% instead of 100. Haven't had any major problems since.

yep, that'll do it.