IIRC that was AMD's (supposed) big advantage over Intel's 64 bit processor; the software. AMD's allowed you to use current 32 bit S/W whereas Intel's required total rewrite of software.
Just my $.02
EDIT: Does anyone remember all the issues when mainstream OS's went from 16 bit to 32 bit?
[ May 13, 2004, 14:34: Message edited by: rdouglass ]