I got the CTO option of the 320gb HDD @ 7200rpm....and notice that *sometimes* it is very quiet (w/ expected windy sound as it spins) but other times it goes through this on again off again cycle of muted clicks and clanks. Its not as loud as that description makes it out but in a quiet setting it is quite noticeable and annoying. It gets louder (sounds like a faster frequency) then goes quieter...this pattern repeats and repeats. Its always a click and muffled rattle that starts it on the faster part. Is this normal w/ 7200 drives? I'm concerned this may not be normal and could lead to issues. Having a questionable HD is not something I'm willing to gamble with. In my experience abnormal HD sounds usually leads to trouble.