Do you need a 64bit os with a 64bit cpu? If not are there any benefits to having a 64bit cpu on a 32 bit os? OR would it actually be slower? I remember one of my old pocket pcs had a 64bit CPU on 32bit windows and it was slow as HELL (1-2 minutes to display a 60k jpeg @ 131mhz).

Im about to get a new mobo and maybe cpu and was wondering if I should get an amd 64bit (that things over 900pins!).

Thanks