updated the mb to the last bios rev. found that gskills f3-12800cl9q-16gbsr will not run in the mb. the mb will post fine with two sticks but add a 3 or 4 sticks and the red ram led come on with this ram. ausu said this ram wont work..gskills says it will from there tech support people. it was my error i bought the ram before the mb came out and the ram list posted.
Have you tried the memok button to see if it will post with more than 2 sticks , usually this can force the mobo to run the meory but adjusting the setting of the ram to force it to post.
Could it also be you may have a faulty ram stick? try each one individually to see if they all post.