90nm CPUs run a bit faster and cooler, and are cheaper (for AMD) to produce. That's why AMD is slowly switching over to the 90nm fab process, starting with the 3000+, the 3200+, and the 3500+. FX models haven't come out in 90nm yet, so you'll have to stick with 130nm. However, I suggest going with a 3500+ 90nm and a very good video card, while saving a lot of money.