Tim the other thing I wanted to say but forgot was that I already have FSX running just fine and never have CTD's or OOM issues it runs smooth for me so why not? I just prefer the 64 bit architecture and well thought out changes to the dynamic variables if P3D such as lighting etc besides I have had a 64 bit PC now for a decade and waiting for everyone to catch up. I run another company and other high level frame heavy models in my current FSX setup without any problems at all either.