It's working pretty great. I own a PowerMac G4 1.25GHz Dual (that's two processors). it's around 5 years old.
Though there is one feature I was disappointed with. I couldn't take advantage of this particular feature because my CPUs are insufficient. It was the video and backdrop effects for iChat.
Oh well, I can live without that. I guess that's a sign I need to buy a new Mac. Maybe in 2008.
