enough of the vertext buffer rubbish, it makes no difference with the newer ati cards since those cards can't mess with vertext buffering, it only works with nvidia cards
the way to get through dantooine with an ati card is to simply go into the graphic options, change one setting to anything eg AA to 4x from 6x, apply the changes, then everything will be ok
however the lag comes back once you re-enter from another area or go into the menu, at which point you simply have to change a graphical option again, eg AA 4x back to AA 6x then play on, its montonous but it will get you through the planet until a patch comes
aside from that it seems some older catalyst drivers aren't experiencing problems so i would try rolling back the drivers if you have newer ones