have only good experiences with f12j mod 9 (and several previous tweak-town builds on different gig-boards)... all low level cumulative micro-code inserts, but it/they have always behaved very well (up5th most specifically)... between all the os-boots I put this thing through - osx, unix, linux, win - it has NEVER looked at me funny or made a bit-mess...
thunderbolt consistent on all those os-builds as well... usb3 speeds??? - hey it's a hack - hurry up and wait... sleep? - I don't bother/don't allow sleeping a box - too many anomalies/pitfalls to various os-sleep/restart implementations, so eff that...
as I posted before, the tweaktown crowd picks it up after gigabyte has moved on and left it flopping on the bit floor...