Topic: Madiface XT and the Mac Pro (up to 2012), USB 3.0 and PCI-Ex.
Having successfully tested the Madiface XT with USB 2.0 on my Mac Pro (Mid 2010), I went on to find a solution to make it work with USB 3.0 there.
German distributor Inateck supplied a test card with the Fresco chipset, which unlike other solutions does not require a driver under OSX (10.8 and up). The inexpensive KTU3FR-4PA features 4 ports. It requires additional power over a SATA connector. An upcoming model will work without.
Result in short: The card and the chipset work. The Fresco has already been added to our compatibility list and seems highly recommendable.
Both in bootcamped W7/64 (Driver required) and in OSX 10.8, I was able to record 192 channels (24/48) in Reaper without any apparent problems. No glitches, no issues of the system beoming unresponsive or so, no USB errors. In W7, I also tested recording to an external 2.5" 2TB USB drive connected to a second port. Playing back the project seemed to sometimes cause disk overload, but this is not USB related. Multichannel recording was not yet tested in Win 8.1 (no driver required) and OSX 10.9, but basic operation is without obvious problems.
Next up: Testing the PCI-Ex Matrox card, with XT and a HDSPe MADI FX in an external case....