Wow, just swapped out my (2) 250gb seagate 32mb cache HD's for a raptor x 150 and another WD 500gb drive. These are WAY louder than those 2 seagates which were slient. i'm almost thinking about returning the two WD drives because of it. also because i thought i would get better performance out of 1 raptor than 2 seagates in raid. but, the vista install took significantly less time to install with the seagates in raid.