i've been digging around a bit, and it seems like ATI users who are using the fglrx proprietary drivers tend to have issues with Unreal-based games in Wine. For instance, Borderlands 2 and Remember Me seem to run flawlessly (sometimes even better than Windows) when running on Nvidia cards, in Wine. On my old 560ti I played through all of Dishonored in Wine, and it ran perfectly. But run them with fglrx and you get about 2fps.
Is anyone aware of any way to increase performance under Catalyst, for Unreal games in Wine? Or is this just a combination that is not meant to be? (And/or would it be wiser for me to wait for radeonsi to get to the level of r600 and possibly switch to that at a later date?)