I'm getting a lot of short glitches on my Mac Pro, during which iTunes might pause for a few seconds, text stops appearing as I type, beach balls etc. I've looked in the console as these happens, and things like this appear a lot just after the hang is over. My disk "RAID Set" is two disk stripped RAID array in Bays 3 and 4. Disk utility says both disk's SMART status is verified, but I've heard that's doesn't always mean their aren't any problems. I started getting this problem while playing videos, but it seems to be happening a lot more often, during times of less demand on the disk, which is worrying :/ Updating my backup as I type this!