I currently have this board GA Z87 D3HP
With i5 4570 and (2x)@667 MHz Samsung RAM which is auto underclocked by the board to 1320
and sadly part is I can't even adjust the Ram timmings. Default is 9-9-9-24. If I adjust to 8-8-8-20/22 then the system will say "OS Missing"
I have used that RAM on my socket 775 GA G41M. Manage 7-7-7-18 @1066mhz with no problem.
So I guess it's the board?