CPU/GPU Underperforming?

So while playing Rappelz (in window mode), I find that the framerate isn't very consistent while under heavy load. It does run much more smoothly when I set the game process affinity to 2 cores and set the priority to high, but it still gets a bit choppy at times.

I also ran 3DMark for some scores in case that'll be useful. It looks to me like the scores are a bit low, as I've seen stock scores of around 13000-15000 for these parts.

Setup:
PSU - OCZ StealthXStream OCZ700SXS 700W ATX12V / EPS12V
Mobo - MSI 790FX-GD70 AM3 AMD 790FX ATX
CPU - AMD Phenom II X4 965 Black Edition Deneb 3.4GHz
GPU - GIGABYTE GV-R585D5-1GD-B Radeon HD 5850
OS - Win7 64bit
RAM - 8GB
No overclocking



I've also tried plugging my computer directly into the wall socket instead of a power bar, but that didn't change anything in terms of the 3DMark scores, so I don't think that's a problem.

Edited by Sei, 07 March 2010 - 11:07 PM.

Are you running the latest drivers?

I'm fairly certain of that, unless there have been new drivers from the past month as I built and updated this in January.