My desktop PC processor is actually a 64-bit AMD, I’ve installed almost all 32-bit Linux Distro on it but never a 64-bit one.
Last night after download a 64-bit Ubuntu I decided to give it a try, and to my surprise the installation and update went smooth.
And oh, it read and used all my 4 GB RAM (added 2 GB before installation), so my lil security research lab on VMware will have at least 4 to 8 OS in it ;)
Travelling Linux 