PC constantly restarts by itself with no bluescreen

[southernstar92]

Okay, so the entire time since I have built my new computer I have had a problem with it - which is that sometimes it will randomly restart by itself - it will not leave me a windows error log, it does not bluescreen and it gives me (seemingly) no hint as to what is causing my issue.
I will be doing whatever I am doing and then bam - screen goes black and the PC is restarting.
The only thing that does show is in my "Event viewer" and it shows a critical error, Source "Kernal-Power" with an Even ID of 41 and a Task Category of 63.
Things I have tried to fix this issue -

1. Swapping out the power supply - It happens with two completely different power supplies, both are very high rated Seasonic units, one gold, one platinum.
2. Checking temperatures - it does not seem to be temperature related as far as the GPU and CPU go as it happens sometimes when both are in the 30 or 40 degree range when I am just browsing the internet.
3. Memory test - Memory test showed no errors on my RAM.
4. Swapping out the power cable to see if that was the issue - it wasn't, it still happens with both of them.
5. Trying a different power socket in a different room of my house to see if it was related to the wiring in my house, doesn't seem to be.
6. Turned off turbo and underclocked my CPU to see if it was a stability issue - it still happens.
7. Underclocked my GPU and turned the fan on it way up - it still happens.
8. Reseating my GPU in a different slot - it still happens.
9. Tested my SSD using SSD life - it is 100%

I am at a complete loss at what to do next - could it be my SSD or my windows installation? Could it be my motherboard (oh god I hope not), what do I do here?
All the parts are under warranty I just need to figure out what it is.
I could send the parts away to the retailer to have them tested but each one that is tested that isn't faulty will cost me $30 and a whole lot of time - I use my PC for work as well as gaming/movies and the like so I really don't want to be without it for 1-3 months.. well I can't afford to be.
Any help would be greatly appreciated.. I am at such a complete loss at what to do at this point, it is driving me insane, I intended for this PC to last me 5+ years and really get my moneys worth but at this point I feel like throwing it in the bin

 

[Patrick]

Either board or RAM if you've already replaced PSU. Nothing else to really check given random restarts.