On Microsofts website, it says that Vista Ultimate contains both 32-bit and 64-bit versions of Vista...or maybe it's just something I read somewhere else. Newegg.com has both a Vista Ultimate 32 bit and a Vista Ultimate 64 bit listed, and for the same price. At the time, the 64 bit was out of stock, so I ordered the 32 bit version thinking there was no difference. Can somebody please inform me if I made a mistake?