RAM/CPU or other error

[JL94x4]

My specs on my PC are as follows;

i7 7700K
Corsair DDR4 26.66mhz RAM 16GB
EVGA GTX 1080 SC
Corsair 750M PSU

I overclocked my CPU to 4.8ghz and my ram to 2900mhz but got a boot failure, so I restored factory and rebooted into bios, saved and loaded Windows, however... black screen followed by 5 long beeps.

I unseated the CPU and there aren't any bent pins, CPU is seated correctly etc. So i turned my focus to Memory, I currently have 4x4GB and my ram slots are in the following order

DDR4_4 (Black)
DDR4_2 (Red)
DDR4_3 (Black)
DDR4_1 (Red)

So obviously running Dual mode would be all 4 running, or 2 in the same colour, so this is what I tried.

2 RAM in 4 and 3 and it doesn't post.
2 RAM in 2 and 1 and it doesn't post.
2 RAM in 4 and 2 and it doesn't post.
2 RAM in 3 and 1 and it posts and my windows boots however, its only running single channel.

I tested the other two sticks in the same slots, same order and get the exactly same result.

Do you think its the Motherboard at fault, or CPU? I've kinda ruled out RAM as they all work in the 3 and 1 slots in Single channel.

Could it be the CPU not allowing Dual Channel?

 

[JasonM]

Did the problem occure only after recent overclock?

 

[ED209]

Could always try removing the CMOS battery and disconnecting the power from the PC for 30 mins. this should clear the bios settings and put them all back to default.

After you checked the CPU did you make sure not to over tighten the cpu cooler when putting it back in?

Maybe loosen off the CPU a few turns on each corner and try again