Power saving mode error.

[Serratedsyd]

I recently built a custom gaming rig with the Thermaltake core p3 SE ATX open frame, inside i have a unlocked i5 core 6600k skylake, Asus 1060 GB gpu, 16gb Corsair Vengeance memory, B7 Sniper motherboard, CX850M psu,Thermaltake Pacific RL360 D5 hard tube cooling kit. the problem im having is every now and then my computer goes into power saving mode and attempts to reboot but ends up going into a bootloop or into BIOS. i have changed my power settings, replaced my memory and motherboard and reseated my GPU. the only thing i can think of is my Riser cable is acting up even though i carefully placed it and followed youtube videos on how to install it. i have another riser cable on the way but i want tips if there is anything i need to change in BIOs or power saving settings. currently everything in power saving settings is set to never. 

[DrMacintosh]

Well you eliminated everything other than the OS and the riser cable from the sounds of it. It could be the GPU since it is in part responsible for the system posting......it could also be the OS. 

[m0k]

Which bios revision are you running on your motherboard? theres been a few updates 

http://ca.gigabyte.com/Motherboard/G1Sniper-B7-rev-10#support-dl