I just got two new WD 750GB Caviar drives and they are making a fairly loud pulsating buzz. I surely hope this is not normal because I won't be able to stand it. I have also never installed a hard drive before. Do I have to format it or something? On my stock HDD on my Mac Pro the partition scheme says " GUID Partition Table" and for the two new drives they say "Unformatted". Could this have something to do with the strange buzzing?