Solved Windows 8 RP - 32 or 64 bit version ?

Hi there, I've been running W8 CP on old laptop for a while now and, Metro interface apart, I quite like it ( I installed Classic Shell to get rid of, or at least suppress, the Metro UI ) and I'd now like to install the RP on my desktop alongside W7. The latter is the 32 bit version although the processor ( Intel dual core 2 x 2.67 ghz ) is actually 64 bit ( which I only latterly found out,...