Yup, this game runs poorly, and even when running very well, just feels like a dodgy console port, or an emulated PS2 game. I played it on similar hardware this past spring (965BE + 4870 512mb) and I was greatly disappointed with how it performed. I have seen it run on stronger hardware, and it struggles. This was before any significant patches were released, so there is a chance that it might have been patched into a better showing since then.