In fact, it looks like I missed some i686 libs. But it's OK now!
So I tested the current git (with the recent Vadim patch included) + this series of patch from Marek.
My config is a RV770 (HD 4850), 2 Go RAM, Pentium Dual Core E2160 @ 2,7 GHz, Fedora 17 (kernel 3.4.4 / xorg-x11-drv-ati 6.14.4 / libdrm 2.4.33).
I play ETQW at 1680*1050 and with the lowest graphics details. The FPS are roughly 30 FPS (average), which is quite playable. Even if there is some lag many times. Now the FPS can grow up to 60 FPS more often! I haven't tested very well, it depends on maps as I can see but the FPS boost is awesome!! Without visual regression. But still some lag many times.