If you're having problems with extremely long load times for a map (1-2 minutes), open ROEngine.ini (in My Documents\My Games\UnrealEngine3\ROGame\Config) and set this:
[Engine.ISVHacks]
bInitializeShadersOnDemand=True
For me, it changed level loading times from 50-60sec to about 10-20. It might have a less desireable sideeffect of some stuttering while the game has to initialize shaders, but if you have a good card it should not matter much.
