Well ati needed ages to fix a OpenGL 4 problem with tesselation. I reported it several times that i compared the results between linux+win and until the latest 10.10 HOTFIX (not the normal 10.10) it did not work correctly. I tested it since i got a 5670... So ati really managed to write worse win opengl drivers - even for more customers
Well, it was fixed after the german c't magazine published this:
They wrote that a nv gtx 460 has 30.6 fps in unigine heaven (dx11), radeon hd 5870 has 28.1 and hd 6870 got 27.7 in dx11 mode. But then they write that OpenGL 4 with hd 6870 with similar settings was only 10.3 fps - they did not mention hd 5 series, but the problem was there too of course. And guess what, ati began to work on the issue, but not when I found the issue with my hd 5670.
what ashit the problem still exists.testin 12.10 now