Basically the tests should be done crossplattform. The raw speed for intel on win is much higher which is really sad. The diff between linux+win is lowest with nvidia, amd performs up to opengl 3 really similar, but has got a problem with opengl 4 (only heaven compared with hd5670). intel however is a day/night experience - lots of apps do not even run on linux which do on win like heaven (with tesselation) or rage (via wine). Haswell, the IVB successor will get a much more powerful - i expect about twice the speed on certain benchmarks, maybe not all. Of course intel could optimize the drivers for a certain workload (like the source 2 engine) but most likely amd will be still faster - only compared the combined cpu+gpu solutions. As always the number of possible sales will impact drivers. It's all about making money.