Using 32bit applications on 64bit machines ois no problem...\n64bit-processors support 23 & 64 bit applications...\n\nRegarding the speed, it depends on the type of processor either Intel or AMD, and the type of task you want to do...\n\nDon`t expect both to respond similarly...to compare different 32 & 64 bit processors while doing different tasks (Ex: Compression, DirectX, etc) try visiting Tom`s Hardware\n\nhttp://www.tomshardware.com/