Originally posted by AlphaTech
Actually the towers can hold up to four hard drives... the stock drive comes in the two up carrier, and they still ship with two others (one drive for each). I'm not 100% sure why Apple says three. It could be that they are listing for the full height drives, which almost no one buys these days. All ATA, and many SCSI drives are the 1/2 height factor, which the towers can hold four of.