Unforunately being at work I can't try this right now but this might be the problem (I was not running SP1 before).

"The crux of the issue is this - Windows Vista Service Pack 1 always enables the Phenom TLB fix on relevant CPUs by default, which can impact performance quite severely in some cases in the name of guaranteed system stability. Regardless of whether you disable this fix at BIOS level, or using AMD's OverDrive tool, it will always be over-ridden by the OS. Thankfully, a member of the Xtreme Systems forum has created a way to ensure that the TLB fix is disabled with a little extra effort - If you're running Windows Vista Service Pack 1 and an affected processor, be sure to check it out."