New computer build keeps crashing/restarting

[MaeBones]

Hi, I just built a new computer. For the most part it runs very well but often it just turns off and restarts itself. I haven't set up overclocking or anything yet all settings are still at default. My components are:

MSI X99S XPOWER AC EATX LGA2011-3 Motherboard
Intel Core i7-5820K 3.3GHz 6-Core Processor
Corsair H100i GTX 70.7 CFM Liquid CPU Cooler
Crucial Ballistix Sport 16GB (2 x 8GB) DDR4-2400 Memory
MSI GeForce GTX 970 4GB Twin Frozr V Video Card
Microsoft Windows 10 Pro OEM (64-bit)
EVGA 850W 80+ Gold Certified Fully-Modular ATX Power Supply

 

[Outlander_04]

Check in BIOS and see if there are XMP profiles for the RAM .
Try the one with the lowest speed