Poor performance with fglrx in openSUSE

Hi, other distros might have the same problem, see [[http://dev.ryzom.com/issues/959]] (last couple of comments).
The game runs very smooth in Windows XP on the same machine at normal/high settings, but aside from the character creation/selection screen, the Linux client is choppy (Radeon HD 4k-series, Catalyst 11.5, 64bit OS) even with low settings.
Are there any tweaks to help boost performance when using fglrx? Thanks

Edit: Tried with Fedora 15 (latest opensource radeon driver), same underwhelming performance.