I have a dual Quad-Core MacPro2,1 with 13 gig of ram. My boot disc is two 1gig drives set up as mirrored raid. I have two other drives - all appear to verify etc OK. A couple of weeks ago it started taking about 6 minutes between pressing the power button and being ready to go. Before that it was much quicker - didn't time as it seemed pretty quick. I assumed it must be some software problem so I did a clean reformat then re-instal of Snow Leopard. It still takes over five and a half minutes. The hardware tests I've done say there's nothing wrong. Zapping PRAM makes no difference. I have a horrible feeling there is something about to fail!! I have a Drobo with 4 x 1.5 TB drives as my time machine which goes back over one year now and is about half full. Does the computer check all this data each time I start up? If it does could this possibly explain the long boot time? Any (other) ideas?