Yo guys, just wanna check, recently just started to play this game after i got my 5870, i see most of the setting can only set High izzit normal?

i'm playing on 1920x1080 res, with 8xmaa(wat's that), i put the vsyn on, some times when the front player smoke me, i'll feel abit slow motion, izzit nomal for a 5870 ?