I'm using a mac pro with 1 GB of RAM, and I have 4 hard drives installed. I found it really a pain that my HDs will go "sleep" themselves. The situation is if you haven't accessed a HD for like 10-20 minuets, it will lower the spinning speed (you can hear the noise!) and then it will give you the beach ball if you want to access it (the noise of speeding up!). WHY?? Really annoying! Is that because I don't have enough RAM? NEED HELP,MAC Geniuses!!