It probably has to do with DAoC taking a lot of CPU time, but that's kind of ridiculous.
Ridiculous it might be though that could be the problem. Is your game heavy on 3D video? 3D video can absolutely cane both the processor and memory. In my view you have the better processor for gaming, AMD is the way to go, though this may not always be enough. What's your video card like? The older the card the more likely it is to tax your processor and memory. You will want a bare minimum of 64MB ram on the card. Use Leadtek or Matrox or another top brand too, not a cheapie.
I only wish I had your MHz and DDR, I'm stuck with SDRAM and a 1300, though I don't play games so it's not so bad.