You guys really dont have idea how much i would like to have nVidia graphic card here as well to show you performance gap between those two. I just set details to lowest i could to get crazy 45 FPS (nothing more i can beat from 4670?! in fight its like 20~30 FPS). Game looks like 10 year old, but its a little bit more playable. Lets get objective again now.
It feels like just some cards are affected by this performance issue. Maybe Michael could be usefull now as he could make a HoN benchmark into Phoronix Test Suite?
try to turn off compiz/kwin and turn of GPU acceleration in firefox and flash.
i write a phoronix post here weeks ago about the same problem this issue brings extrem mouse input lag! because the fps drops in some situations very low. try to pull out a intem out of your back pull a intem on the floor the mouse will lag like hell!
then i turn of everything Kwin/Firefox-GPU-acceleration/Flash-GPU-acceleration and so one.
now it works playable.
I have Intel i3 processor, with hd5470 amd card. Running on Ubuntu 11.04 with catalyst 11.7. Dont sure what fps exactly is, but i can play without any lags, sometimes in big fights in have some performance issues but not critical. Settings are set to Mid->High. Also i prefer closing other programs(especially after firefox 6 update, causing some huge memory leaks for me, even when only firefox is running). But in overall - everything is working fine. BTW i have 2 video card in my laptop because of i3 processor.
their opengl renderer ist terrible.
i used to play the windows version via wine because it would run faster with the direct3d renderer via wine than the native opengl renderer.
edit: without a firefox browser i do have 64fps vs 29fps in the linux clind!
windows clind in wine=64fps
nativ linux clind =29fps
even the windows clind do have better effects!