Keeps restarting but will start fine after psu turned off and then on again

[K755]

Recently I've built a system but the Computer will keep restarting when trying to boot. But it will start fine after the power switch on the psu is turned off and then on again.

Specs:
Intel 6660k
Corsair h100i
Gigabyte
GA-Z170X-Gaming 5
Ripjaws ddr4 2400
Evga supernova 650w
Asus gtx 660
Samsung 250 ssd
Seagate 2tb hdd

All the parts are brand new apart from the graphics card.

 

[brispuss]

This suggests a problem with the PSU.

First make sure all cables/wires are connected properly.

If still have issues, then try the PSU in another computer, and/or try another known working PSU. If necessary, borrow computer and/or PSU from neighbor, friend etc.