usb 3-

I want to do some serious editing using Final Cut Pro X on my Mac Pro 2.66 Quad Core Intel Xeon, and I was wondering if I installed a HighPoint RocketU 1144AM PCI-E 2.0 x4 Quad-Port USB 3.0 Raid for Mac (there are slot available) if I coud use a USB 3.0 drive rather than a Thunderbold drive, because the USB drive is so much more affordable?

Thanks

Hal