hmmmm.......I'm not for sure on the FPS thing.
Since the comp with the 9600 XT is at my dads, and I am at my moms as of now i cant check the FPS, sorry =(
BUT, the computer here at my moms just has a geforce mx 440 AGP 4x, and I am running BF Vietnam here, believe it or not, at a VERY playable pace with everything put on low, but it still looks pretty sweet.
As for the FPS, you wont have to worry about that dude, trust me.
Let me just say, that if you have never experienced a fast computer before, or one with an actual decent video card, you will be BLOWN AWAY with the performance that you will get out of the 9600 XT. I can run both UT 2004 and BF Vietnam with EVERYTHING TURNED UP and on 1024x768 with barely any slowdown. It runs almost perfect. The only thing about BF vietnam, though, is that it is a little bit "stuttery", but after you play for around 2-3 minutes and your computer gets "adjusted" to the level, the gameplay gets smoothe, and it starts running extremely good.
Dont worry, you wont be let down by the computer that you will be getting, and it will EASILY blast UT 2004 and BF Vietnam away, that, i can guarantee!