Not entirelt true I'm afraid as GP3 2000, suffers enormously if you turn on FSAA.
Also Unreal Tournament's performance does start to introduce a few occasionally pauses and hiccups, or the odd frame rate drop off. Note that this is not apperent when running UTBench, which virtually gives the same scores up to 1024 x768. Go beyond that resolution and performance nosedives with 4 x FSAA.
Probably worth noting that with fast moving games like Unreal Tournament, switching on FSAA does not seem to give much of a noticeable visual improvement. The improvement is there, but you don't have time to notice it...!!!