Hello All! I have a mid 2010 mac pro v5,1 OSX 10.6.8 and am having trouble trying to upgrade it by installing a USB 3.0 PCIx card. It seems like so many others have had great success with this: http://forums.macrumors.com/showthread.php?t=1238494 However when I tried it doesn't seem to work. When I installed a similar card with the NEC D720200F1 chipset, hooked it up to the internal power, and after trying various PXHCD.kext files (all which have worked for others on other forums) mine doesn't seem to want to recognize anything plugged into it, USB 3.0, 2.0, or otherwise. What really doesn't make sense is that the PCI card and USB connection both show up in the system profiler. The only thing I can think of is that there is some other kext or some other file that is interfering with the proper functioning of this card. (I had a similar problem a while back with a LexarUSB.kext that was interfering with reading DVDs in my optical drive, but once removed it was golden....how someone figured that one out baffles me lol). Anyways if anyone has any suggestions out there, I would love to try them out. Thanks in advance for all your help. Cheers!