prove this!... and i'm sure you "can't"
you only don't get a acceleration on lowend cards like hd4350 or hd4550.
you need at minimum a hd4650 to get a speed up compared to the cpu.
and this is your real secret point you claim linux users only use lowend hardware and on lowend hardware the hd4000 generation can not "accelerate"
anything above hd4650 is much faster than the "CPU".
(rolls eyes and gives up, wonders if it's too late to sign the petition)