what is your cpu and its stepping?
i have this board too and using 2500k .it works at 4.6 ghz greatly with oc optimized configuration with a little change(it could not pass stability tests with default setting so i have changed the diagram of voltage from 5 to 3 ) passed intel burn test and prime 95
in sandybridge max core voltage and the diagram of voltage against load is important not only the vcoreNow ive compared all the voltages for the auto-oc's on their default voltages and i can safely say they do not change (PCH, VTT,VCCSA,CPU PLL). So then i thought maybe my vcore is insufficient, therfore i tried a 1.4 FIXED vcore with LLC of 2 on the 4.4 oc and the 4.6 oc. Still nothing...
i think your vcore is so high,1.4v, at 4.4 ghz try to use the default oc optimised with little voltage diagram
i hope my experience hepls you