Strange errors when computer left alone for hours

[KainArkanos]

So I've come across a strange error that's really hard to describe on Google search to find a solution.  I've rebuilt a computer using mostly parts that I'd already had in a previous computer that worked completely fine with zero errors, with the exception of a change in motherboard and a change in graphics card.  Ever since the change, randomly the computer will either lose output to the monitor completely, won't respond to any mouse movement or key presses to turn back on the screen, which I figured originally was a faulty sleep timer for the monitor, but even after turning it off it still continues, other times I'll experience a complete slow down of audio and video, which is only fixed by a double restart as the first restart seems to hang completely on a blank screen after the computer is supposed to hit the bios screen.  Seems to only really occur once every few days though, doesn't happen every time I leave the computer alone for hours.

OS: Windows 10 Home 64-bit

Specs:

Motherboard: Asus Sabertooth X79 bios ver 4801
CPU: i7-4930k @ 4.3 GHz
RAM: Gskill Ripjaws Z 16(4x4) GB 1866 MHz

GPU: Gigabyte GTX 1080 Xtreme Gaming
Storage: Samsung 850 EVO 500 GB
WD Black 1 TB HDD
PSU: EVGA Supernova G2 1300W
Soundcard: Creative Soundblaster Z