I can pass 3dmark06 @ 750mhz, and I'm stable @ 725mhz for 20 minutes in ATI TOOL artifact scan.
As Moots said 800mhz is a little too much for stock gpu core voltage, but I didn't manage to crash right away. It went about 30 seconds into the 3dmark06 text, and let me tell you it scales extremely well with core speed. I noticed 10-15fps difference in some areas, and I started the bench around 110fps when entering the scene!
I'm definitely ready to get my second card back from rma!
*edit* Apparently my HD4850 will do 735.93 on the gpu core and pass a 10 minute session of ATI Tool.
Edited by 13 3 @ 7 l 3 13 0 y - 7/8/08 at 9:44am