Quick requirements question

I'm looking at an A64 w/ a K8T800 board, but do I need two sticks of registered ram. It looks like some of the new AMD chips need it and some don't.

I'd like to run 1 chip for now, till I can buy another corsair PC3500 stick.

Thanks for the help.

You only need 2 sticks of registered ram for the Athlon FX51 (opteron 1xx clone), the Athlon 64 3200 can use normal stuff.