Dead CPU or motherboard, split second boot when 8 pin plugged in.

[birdmjubs]

My rig:
Cpu: x5675
Mobo: p6x58-e ws
Psu: hcg antec 750w btonze
Gpu: r9 fury sapphire
Ram: gskill and Samsung ddr3

I opened my back panel and switched my ssd from ide to sata port. When I booted my computer and went into bios to configure, my system shut down after I saved it it said oc failed. I had overclocking fails messages rarely (I was undervolt/oc with the GPU so maybe that's why) but they either still and i even put more voltage on the PC and lowered it. So after it crashed I reentered and it shut again after going into bios. After that it didn't turn on again, reseted CMOS and it turns on less than a second with I flip the psu on and off (only booted with no post when I unplugged cpu 8 pin). Tested the power supply by swapping it and using it on another computer (and tested with another psu) so it's not the psu. I took out the cpu, restated it and replaced paste, tooked it hdd and ssd, and even rebuilt my whole PC to fail. So do you guys think its mobo or cpu or other. Thanks in advance.

 

[Kashimi]

If you were messing with voltages and now it isn't booting, it's very possible you fried the CPU.

Can you get into your bios at all?

 

[birdmjubs]

It doesn't post and it can't boot when the cpu atx motherboard 8 pin is connected. Pretty sure 1.35 v is stavle for 4.3 ghz. If not, big oof.

 

[Kashimi]

Your overclock may not be stable at that setting. If you can't get it to post at all, try to reset the cmos, unplug the PSU, remove the cmos battery, hit your power button a few times, replace the cmos battery, hit the power button a few more times then try to hook back up your PSU and see if it will post.

 

[birdmjubs]

I did do all those things twice to no avail. The only lead I got is the 8 pin.

 

[Kashimi]

Sounds like you're out a CPU.

 

[birdmjubs]

Yeah I thought so too, if it is the motherborad then that would of sucked because ws x58 are rare and are meant to be durable anyway. Thank goodness for the x58 platform because cpu was only 40 bucks. Thanks.