How much RAM are you running total and how many sticks total? I have this same motherboard with G.Skill 4 x 8 GB installed and it is virtually impossible to get it to run stable at 4000 MHz. I have done it in the past with almost all manual RAM timings and voltages. It would run fine for a day or two and then start getting errors. The only stable speed I can get with manual timings and voltages is 3800 MHz. DOCP will only work up to 3600 MHz for me on this board with this RAM.