New CPU upgrade causing trouble, help!?

Hey everyone, just got an intel E8500 today for my computer, so knowing a little bit about how a computer works i managed to replace my old one with the new one. Got everything put back together and fired it up. The computer booted fine with the new CPU in it, and i got into windows fine too. The trouble started when i went in to a game (Age of Conan), bad graphical lag started already in the intro and when i finally got into the game it was running at 2-7fps. Now, the CPU i was running with before an E4300 i had an fps of about 25-65, so it is a dramatic decrease. Fearing the worst i put back in the old CPU to see if the graphic card might have been damaged, but no the computer now performed fine in both Age of Conan and 3Dmark06 with the E4300 back in. So i looked around the net and being a newb i found out it could have something to do with my BIOS not being up to date, so i updated the BIOS. Then i put back in the E8500 hoping the problem had been solved, but no. The fps in the game was the same as before and the 3Dmark06 score was still signifigantly worse than with the E4300.

So i ask if anyone out here got any ideas to what might be causing this? Could it be that the mobo doesnt support the much newer E8500? The mobo is a ConRoeXFire-eSATA2 http://www.asrock.com/mb/overview.asp?Model=ConRoeXFire-eSATA2

ANY help is much appriciated!