The only thing I see is that the Performance Cap is no longer there, where it was with 331.40 (see sensor page).
With the other drivers it was VRel and Util listed as performance cap.

What are others getting as a Perf Cap with SLI setups?

I don't have anything listed on my GTX 770, but when I was having issues with it I had a Performance Cap of Util.

I would fire off a couple of emails to EVGA and NVIDIA, EVGA might have a newer BIOS for the cards, or be able to fill you in on any known issues.