The best way I can think of to describe it, is it feels like I went from a celeron 2GHz to an A64 3200+
. In all seriousness, it made a huge difference in the feel of the machine. Windows loads a TON faster, apps load a TON faster, and my gameplay (EQ is pretty much all I play) has become much more enjoyable. All the points in my of "lag" day to day usage I had hoped were just the slow hard drive, were indeed the slow hard drive. I would say do this upgrade first above and beyond any other upgrade, but now after finding a 1GB stick for less than $150, that may be the best first upgrade. That is, of course, unless you are doing a lot of "disk heavy" work on your machine.