Recently I endeavoured to upgrade my 2010 MacPro to support USB 3. I purchased a 2 port CalDigit USB 3 PCI Express Card and a Newer MiniStack Max Enclosure (USB 3 w/BluRay) from OtherWorld Computering. After installing the card, installing the USB3 driver, and connecting the Ministack Max I have come to learn that apparently Caldigit USB 3 PCI Express Card does not support a USB 3 hub including the USB 3 hub that is built into the Ministack Max. When all connected, my Mac experiences kernel panics upon start up but manages to boot itself up after the third attempt; however, the USB3 peripherals won't work or are flakey at best. I've spoken with technical support staff from Caldigit, NewerTech, and Other World Computing and gleaned the following: 1) Due to the (old) chipset used, the Caldigit Cards do not support USB 3 hubs. 2) The Ministack Max is not intended to be used in conjunction with an after market USB PCI Cards on the Mac. Apparently it will work on Windows PCI Cards (running Windows) and on MAcs with built in USB3, although this I cannot confirm. 3) Other World Computing is unaware of these issues and will gladly sell you these items, despite the known incompatibility issues. Aside from my buyer beware message, I would like to know if anyone has had any luck using another USB3 PCI card with a USB hub. From what I have seen in various forums (and from my own limited experience) is that it doesn't look like USB 3 is a viable option for Mac Pro unless you are content with limited functionality (No hubs, card readers, etc).