My MacBook Pro (mid 2009, 15", 2.53GHz, 4GB RAM) with original Hitachi 250GB HDD (Hitachi HTS545025B9SA02) does hibernate when I close the lid and hibernatemode is set to 1. When I replace the HHD with a Seagate Momentus 7200.4 500 GB (ST9500420AS), the MacBook does only sleep but not hibernate (hibernatemode is still set to 1). Even if battery runs out of power, the macbook does not hibernate and after getting back to power it has to boot. I backuped from the new HDD, switched back to the original HDD, restored the backup and hibernate does work again! So, why does my macbook not hibernate with the Seagate Momentus 7200.4? Does the drive need to much power? does the macbook need to know how much power a drive will need? Any ideas?