When I raise the mem over 1500, I actually lose points in 3dmark 11. I now have crossfire, but when I ran my one Myst, I overclocked the core to 1253 ( i believe, it was close to that) and left the memory at 1500. I believe my 2500k was overclocked to 4.5. My score was P9614. That is with stock voltage and 20% power limit. Could you try those settings in 3dmark 11 performance and get back to me? Also, do you have the 028 bios like I do?
I love this card and that's why I bought another and crossfired them. Gotta love it...P13300, graphics score over 17000. These cards are beasts and I beat my son's overclocked Sapphire 7970 vaporX with 3770k by over 2000 points in 3dmark 11 performance.