Steve and I are seeing different performace profiles between IE 6 and Mozilla 0.9.9. I'm running a 256MB 700Mhz Celeron on Windows ME. IE has always been dog slow on this system, pausing while loading pages, even on a DSL line.
I have done some experimenting and how I load new pages makes a big difference when using Mozilla. I tend to keep a lot of browser windows open, somewhere between 3 and 5, and when I hit an interesting link I have the habit if right clicking and selecting "Open in New Window", which is real slow under Mozilla. Selecting "Open in New Tab", on the other hand, is very fast. I get the feeling that the big performance drain is XUL and handling all the chrome.
Two more exciting bits about Mozilla: