The stock drive has a 16mb cache, correct? I assume I will get a 320gb Seagate Barracuda, or WD. I want to purchase a second drive and possibly raid it, or just use it for time machine. I will most likely purchase an identical drive; however, just out of pure curiosity. Does a 32mb cache affect performance that much? Also, why would the 10,000 rpm Raptors be considered a novelty these days? I've ran these puppies in Raid 0 since 2003 on my PC. I've read a few posts here that suggested that they're a novelty now days because of the larger cache and platter sizes of modern SATA3 drives like the stock Apple drive. Can anyone explain the theory behind this, I don't doubt it, I'm just curious why. Any insight, feedback, or comments would be greatly appreciated. Just to prevent any pointless posts or confusion. I am not looking for maximum space. 320gb's is more then enough for my needs. I also know all of the risks associated with running a raid array.