The core limit on his card might be higher because of the XFX bios.

Anyway, here is the maxed out core and memory ( cant go over these limits because of the CCC limits ).
This Asus DirectCU 6850 is running nice and cool. Under 65C even at this speed. Rock stable.
Those who are getting low scores in vantage, update to 10.10c hotfix. I found my card was not getting loaded properly. the log showed the GPU load was dropping to 70% for fraction of a second causing stutter i was seeing on the screen.
10.10c hotfix fixed it.

Here is run at 1000/1250.