Hey mate. Yes, I've already done that with no success. I have been in dialogue with Eric from Apricorn who do his own system tests for days with Mac Pro 3,1 and Duo with Win 7 and Win 10 and could not get a consistent successful result. However he had no issues with the Mac Pro 5,1 booting correctly. He also said that other are still having issues booting from this card on 3,1's. I don't know what you guys are doing on your Mac Pro 3,1's to get it to boot. I'd love to know. My intention is to have 2 x SSD's on the DUO. One with OSX Mavericks or Sierra, and the other with Windows 10 or 7...whatever will boot and work reliably every time. On a 3,1 system. Any takers who have done this successfully on this exact system model ??