Just got a new dual 1.8 with upgraded 160GB drive. Great machine, but the hard drive seems fairly noisy. It makes a fairly pronounced crackling noise whenever accessing data. The noise itself doesn't sound abnormal (the drive in my powerbook makes a similar but less frequent and much fainter sound), but it's just kind of loud (louder than fans, for instance). Is this fairly typical of this drive, or is it something to be concerned about? Thanks.