My brother called me up today and said that Leopard by default is running in 32 bit mode. OKay fine whatever. He said to reboot and when you see the apple screen to hold the numbers 6 and 4 on the keyboard and it will boot in 64 bit mode. I confirmed my Mac Pro is running leopard in 32 bit through Terminal. Any thoughts on this? Any issues or positive aspects to running in 64 bit mode? Does this need to be done on every bootup? I don't want to fuck anything up since my system currently runs flawlessly.