Comments: i got this yesterday for a 12" ibook and replaced the stock toshiba 40g 4200 which was INAUDIBLE. i realize a 5400rpm drive will make more noise, but this drive is WHINING. its loud enough in the ibook that i cant focus when im reading a website. its like a high frequncy signal that subconciously fatigues my head. anyway i think its having a problem b.c there is no way so many reviewers (40gb, 60gb, 80gb) would not comment on this noise. as stated in previous reviews the seek times are noticably faster than 4200rpm drive. the heat output is slightly higher but not uncomfortably so. if it wasnt whining it would be 5-star upgrade. i will rma and see if new one makes the same sound, if so i would seriously recommend mac owners to look elsewhere.