Reply to S4 ruined my gig last night. Help.

Okay, I've been using TP2 since the day of release and TP1 before that. I have used various controllers and have lots of experience tweaking my machine to work flawlessly. About a week ago I decided to buy the s4, I'm so invested in TP2 that I might as well have the flagship controller right? After countless hours of testing at home becoming comfortable with the layout and not having a single issue (None what so ever)... I decided to use it for a gig. Fresh restart, ran my optimization code for win7 as always... And when I started playing a song would get about halfway in and then start to slow down progressively to a crawl and eventually freeze. The tempo faders on the screen didn't move, the BPM values for the tracks didn't change on screen. The fix I found during the set was to simply yank the USB to the S4 and plug it back in quick and audio would be back playing normal for another 5-15 minutes before doing it again. This happened at least 5 times in my hour and a half set. And it had never happened in the countless hours of practice at home. I made zero changes to the settings and everything was plugged in to the same USB ports I always use (I label them). Be aware my CPU usage never spike above 40-50%, and I can play for hours on end at home with zero issues. What in the hell could have happened last evening ? I have seen a few posts on the net about this but it seems no one really has looked into why this happens. They blame CPU manufacturer (AMD) or the whole Win7 thing and like I said, countless hours I have played on this exact setup at home with no issue (and gigging with control vinyl/CDs and other midi devices before purchasing S4). So its not the laptop. I just can't fathom why this happened last evening only. I'm extremely frustrated and embarrassed over what went down last evening and I refuse to use the s4 live until I nail this issue down. Does anyone have a clue?