According to a forum post by Epic Games VP Mark Rein, an option will be available on the PS3 version of Unreal Tournament III for installing approximately 3.5 gigs of content on the hard drive:

"Yes there is an install option which places a bunch of the commonly used content on your hard drive to speed up loading and texture streaming times a bit. It does not install everything - you still have to put the disc in the drive to run the game. The install is absolutely not essential. The game runs just fine from theBluray and load times aren't bad but if you're going to play the game a lot, and you've got an extra 3.5Gb on your hard drive, then you might as well do the install because the few seconds you save here and there will add up over time. If you want to free up space you can delete the installed data at any time."







Via N4G

pretty usefull although i would never do this myself, i just wait a few seconds more..

Quite interesting, but I think its only useful if you play it for hours everyday.
Anyways it needs too much space compared to the size of the PS3s HDD.

Well, if you consider the people with 60 & 80GB's, it's not THAT much. Demos are only like 1.5 GB max, and this increases the loading time dramatically. DMC4 is supposed to have an HDD install for about 4-5GB - no loading times at ALL. You can run around everywhere without any loading times whatsoever. If you ask me, it'd be worth it for that kind of effect. I've heard texture loading in UT3 can take a long time.