Could be down to a shitty PSU.
That's just a "could be" though.
Might take a little work to get to the bottom of this.
Start with listing the full system spec including the motherboard make/model and psu make/model etc.
Corsair 750D :: 750W DPS-G:: Asus x370 PRO :: R7 1800X ::16gb DDR4 :: GTX 1070::525gb SSD::Coolermaster 240MM AIO::