How can that be?
$ export vblank_mode=0
mobility x1900 yields 1400 frames
HD5850(profile high) only 1200
distribution is debian testing, with kernel 3.8 (liquorix)
Also, I noticed current r600 driver on 5850 is EXTREMELY inefficient when it comes to textures.
For example, in urban terror 4.2, map Cascade, when player looks at fontain that is essentially moving (multilayered?) textures the fps goes down to 20.
But if player rises head straight up, it goes to 80 fps.
On simple maps without this, there is no such issue.