what is the PSU brand? some generic brands can't really deliver the labeled wattage, what can cause problems like this one, low frames, high gpu noise, because the video card could be working under the required voltages.
at 1024x600 you really should be getting better frames.
Now that you mention it my computer does sound very loud
I'm not sure what the brand of the Power Supply is i think it was bundled with the tower
Would purchasing a better quality Power supply possibly fix this problem?