Yeah.... i believe you should have scored abit higher. You sure you have the correct drivers installed and everything? Do you have alot of extra processes running? Are you getting artifacts? What is your temp on your gpu during the test?
If all of those check out, im not sure what could be the problem. You could overclock everything alot more, you got an opteron, im assuming your going to overclock it quite far (if possible).
Its 3dmark06, its resolution is 1280x1024, 06's reso is stock 1280x1024 and i doubt he would have changed it in one of the previous' tests. I could be wrong, but i dont think so.