Okay, I've just received my 3 750Gb Spinpoints and slotted them in. I don't have anything else added onto my MacPro Jan08. I want to make the drive in bay4 an alternate boot drive in case of problems. Any recommendations? I'm thinking of using Carbon Copy Cloner and just cloning the whole of Bay1 onto Bay4. I did insert the original 10.5.1 system disk but it wanted me to do a restart - I was hoping it would just let me do an installation into Bay4. Pro's and Con's?