In this
interview with Mark Rein on Spong, he explains the reason for slowing down
Unreal Tournament 3 on the PlayStation 3. That's slower motion, not slower framerate as that's two different things. The game isn't running slower on the PS3 because of hardware. Can't say I disagree with him. When playing between the two I'm a lot more accurate on the PC than on the console.
Gears of War is a good example of this as I blew through the PC version on hardcore mode but I had a lot more trouble on the 360. There's other little tidbits in the interview such as making UT3 appeal to a wider audience.