I think it's a matter of how much of a jump you make that results in any noticeable difference. The only time I've seen noticeable change is when I upgrade a CPU. Ram only seems to help the HD seek faster by not accessing it as often. So upgrading from a 5200RPM HD to a 7200RPM HD can result in good speed gains also. If you are constantly pushing the ram to use the swap file. What did you have before upgrading to 512? ScottA