Still can't connect more than 4 cards on my H81 BTC Pro Board. Five or six cards trips a reboot right after i start ccminer.

rolling back nvidia drivers, maybe that will sort it out.
I have the same H81 BTC board, and running win7 x64 it wasn't too hard... Not sure if you are on Win or Linux.
I was running just 4 cards for a few weeks, but when I went to add the newer two cards, I added them one at a time, and just rebooted it a few times.
The 'finding new hardware' process took forever to complete, but I just let windows find each card, then I started up the miner, saw that it was working, and then went about adding the 6th one the same way.
I did have to roll back a driver once after I installed it and it made mining slower, and that was essentially the same process, because when I fully removed the driver, all the cards went to discovery and re-installed using the driver that comes with the OS.
Then I stepped up to the newer Nvidia driver from there.
Hope that helps.
I also have EVERYTHING plugged in... all the MB plugs and powered risers using unpowered cards.
The cards pick up fine in Win7, and they all work fine until i put load on them with ccminer. They are EVGA 750ti Superclock GPU's and i'm using the Asrock risers. I had three 280x AMD gpu's on the board previously, and that worked fine. So it looks like it might be board issue.