During W7 boots and when going thru receiver, it will be displaying out of sync signal instead of the GUI boot up info until Windows "Welcome" screen appears. However, if signal goes straight to monitor only, no problem at all and it will see all the boot up info. Unfortunately my monitor does not have any audio/speakers.
I also have Z77 and i5 2550K SB set up, same set up and no problem at all, just the 4K IB set up has this problem.
Try current released driver, beta driver and 10.2747 all have the same problem.