I haven't had a chance to play too much with it yet, I was too concerned about the temperatures (pushing almost 60ºC under load). Once I get a better HS on it I'll push it higher and see how it performs. So far it seems to be quicker than the dualie box, which is what I expected. 90% of the things I do didn't use SMP, so the only real advantage of SMP was multi-tasking.
Memory performance is definitely MUCH higher, the 76x chipset isn't exactly know for stellar memory performance.
AGP performance seems significantly better as well, which is also what I expected.
As for going back to a single CPU system, I got an offer I couldn't refuse. I was able to completely switch platforms without spending any money, & the new P4's were just too damn tempting.
Viper GTS