I have this same board currently running 6 GTX 1070

Win 10 creators update. without this creators update the cards hash at 2 mh/s
1.d bios
gen 1
4g enable
skylake cpu
4gb memory
Virtual memory setting 3000 -20000
I wouldn't say it's stable though
6 gpu's run about 12 hr before restarting
5 gpu's runs fine
7 gpu's claymore hashes for a few min then restarts...

Im going to upgrade to the newest bios tomorrow morning there is a 5/2017 release.

any other tips

PSU are 2 750 watts
1 running motherboard and 3 cards the other running the other 4
cards 5 asus Republic of gamers cards
1 white asus card
1 Founder edition but with this card claymore just restarts not sure if its the card or just the system becoming unstable for software reasons.