I did a little searching on the internet and I found this post:
"I mean I had some trouble with my USB 3 drive on the Asus p8 p67 pro (B2) USB 3 ports. At first, I had to reformat the drive 2 or 3 times before Windows could read/write it via USB 3. Every so often when I switched the drive on, Win told me again that it had to format first. I could safely click this away and use the drive nonetheless. However, after updating to NEC drivers 2.0, it insisted on the format, and I had to revert to the old version. (Or save the data over USB 2, then reformat and transfer them back.) Stupid message still kept popping up, of course.
I took this for a Windows bitchiness until I found it was gone with the ASRock board (B3), for which I swapped the Asus. Sure, the USB chip on the ASRock is not from NEC but Etron (never heard of the brand before). I have no idea if it is an Asus or NEC problem. I also searched the web for it, but found nothing.
Whatever it is, it's curious, at the least, that Asus comes up with a new revision right after the SB revision, now fixing the USB 3. Rumor has it that rev 3.0 consists mostly of refurbished B2 boards, and returned, that is, used boards are sold as new ones. But if this true, it's certainly not only Asus."
http://hardforum.com/showthread.php?t=1578865&page=112
So it sounds to me like Asus was having issues with the B2, which is the revision you have, right? It looks like other people were having issues as well. Sorry if this isn't super helpful, but I have a feeling most people (like me) don't use USB 3.0 (yet). Actually from this thread it looks like a lot of people are having many issues with different things in general. o-O