If you are talking form factor, smaller is definetly faster. If you are talking gb size, then that is dependant on the manufacturers. A deskstar 10gb hdd from ibm is faster than the seagate 7200rpm drive at 8.4gb. Technology is the key. There are scsi hard drives out there past 20gb's that would blow any ide, eide, udma, and alot of smaller scsi drives too. The only problem here is cost. These drives are BRUTALLY EXPENSIVE.