I believe like Spikey Richie states it is more in line with the virtual memory(VM) allocation. I for one run a normal 450k in my Firefox task manager situation.

I was using that amd mini city gizmo and it would run my virtual memory up to 800k if I used anything else plus that window. No longer running that gizmo for the mini city and my VM is now hovering at 162K. Different web sites need certain sizes of memory for complete operation. Seems AMD Users web site is a hog of memory... Just FYI !