I have an HD 6870 which seems to be bottlenecked by my Phenom II 1035t x6 @ 2.6GHz.
I'll have it replaced by the end of the year with a 3570k, the annoying thing is by the time I do replace it, I'll have had this
setup for almost a year.
All games that aren't CPU intensive run fine. If the map is too big or there are too many players/npc's on the screen I lag.