the faster the rpm's, the faster the drive will be. the rpm's are how fast the hard drive spins, so it will be all the time. 10,000 rpm drives are nice, but they are pretty expensive IMO, and they don't offer a lot of storage for the money. I would stick with 7200 rpm drives for now. if you get a maxtor diamondmax 10 with 16mb cache, it's almost as fast as a 10,000 rpm drive anyway, at a much lower price.