Problem with 4 slots

[miro111]

Hi yesterday I try to built my pc

Core i7 6700K
MSI M7 Z170
4x8GB Kingston Savage 2800

but it works only if I use only 2 slots (1,3) or (2,4) but If I put RAM in all slots it doesnt boot. I tested RAMs and motherboard with diffrent combinations and everything looks fine. Could anybody help me?

 

[kanewolf]

Are the 4 DIMMs a matched set or are they "mix and match" ?

 

[Tradesman1]

For 2800 and 32GB might well need an OC of the CPU and/or additional DRAM/MC (memory controller) voltage