Just tried the new update, performance are really good.
* OpenSuse 13.1 (with latest update at the time)
* AMD Radeon HD6870 x2 (crossfire)
* Catalyst latest beta 14.6
The game is almost on max settings, 1920*1080 (motion blur stuff disabled). I played few hours without any issue and the fram rate seemed to be good & stable.
This is a good improvement since the latest versions crashed / were unplayable / crashed again / run badly on low settings.
It seems we can start playing witcher 2 on linux & amd now