mininig 12 x NVIDIA on the same mobo - problem OC

[igotek]

MOBO: Intel Pentium Skylake G4400 CPU + 4GB DDR4 RAM + Biostar B250-BTC Pro or Esonic B250 Gladiator Motherboard

if I use any OC software, the system starts to use high cpu and the system freeze. Mining keeps up but so many freeze.
This is only on these two mobos with 12 x GPU. It is realtod to memory clock.

if i use -200 memory, no problem. but if i use +200 memory clock the system freeze.
is there any way except to use more powerfull cpu ?

if you use one of these mobos, what are you doing about it ?