[lucienpalmer]

Yes, OWC makes a PCI card that you can plug an SSD drive into and get the drive's full SATA III speeds. The down side is that you are kind of 'wasting' a PCI slot because its capable of so much faster than just SATA III. (Look into SSD PCI blades. Sometimes OWC sell old and open box deals in they famous semi-annual Garage Sale). Although, running a super fast boot drive only really helps for booting and launching programs. You aren't going to get Pro Tools to perform better. Faster storage is more important for your projects to live on. Put your projects on a PCI slot.

BTW, if you only have 4 memory slots, then it's only a single processor machine. Dual processors would have 8 slots. That's a shame. I just looked at the specs you posted, and it's possible your old 8-core MacPro will perform better with Pro Tools than the newer 4-core MacPro.