I really do not understand why ati keeps two sets of drivers for linux. One good and one not so good. Why not open up their best driver? Is this mockery?
OilRush runs on middle detail @ ~17fps 1920x1080 on my AMD 6970M with mesa 8.1-something and ColorTiling2D in xorg.conf (not sure if that matters), no corruptions or anything, just a little slow to play, but hey I had the first rig, then went on to the next and then noticed, boa you just played that game for ~30min already ^^
I was also able to play Trine 2 with my Radeon HD 4670 using only the stock R600g drivers that come with Fedora 16 and with a CPU that was actually below the minimum spec. Played through the game twice.