Now I have to install a new device into my MacPro to be used as a Photoshop's scratch disk for my photography work. I already own a Maxtor 6Y250M0 which is a SATA 1 hard drive (1,5 Gb/s). Reading the MacPro manual it seems I can't put it because the manual says it only works with SATA 2 (3 Gb/s) or SAS. Do you think I will break anything if I try to put my 1,5Gb/s inside? I have also to add a PCI card to expand USB and FireWire ports, which one should I get? Suggestions?