PC shuts down like power cut

[Trigeminal]

OK guys, just completed new build about a month ago and need some advice. My new build is as follows:

Silverstone FT02-B
GIGABYTE GA-X58A-UD5
Core i7 930
Thermalright Ultra-120 eXtreme-1366 RT Rev. C CPU Heatsink
OCZ 6GB (3 x 2GB) DDR3 1600 RAM
SAPPHIRE Radeon HD 5850
SeaSonic X650 Gold 650W Power Supply
Western Digital Black 750GB HDD
Western Digital Green 2TB HDD
Win7 x64

For the first 3 weeks I had only 1 crash. Then after using it for 3 weeks(about a month ago now), I had 1 shut down on Friday, then 2 on Saturday, and then 5 or 6 on Sunday. I say shut down because it was just like what would happen if you pulled the power cord, and it required me to press the power on the front to start it. The crashes seemed to be more frequent to the point I was lucky to boot into windows, sometimes it would crash on the bios,, and several times in memtest (though no ram errors were ever present). I thought it was the power supply, but I wasn't positive, so I changed the setting in the bios to turn on with power loss, but the computer still required me to push the power button on the case to restart. So I assumed it was the mobo, until I chatted with a friend who stated that power supplies and mobo have fault protectors that require manual restart to prevent damage.

I had no overclock on and then went to standard motherboard bios settings with lower voltage for ram. The crashes were less frequent, but they still occured quite often. I was quite busy with school so I pulled out my old rig and set this aside until my big class was done.

When my class finished last week I tested it and it still had the samee problem. So I ordered a new power supply, it came on Monday. I was installing it and noticed two of the Peripheral/IDE/SATA modular power cables were loose and easily fell out. I wondered if this was the problem, but figured I'd try the new power supply first.

That power supply resulted in 72 hours straight with no crash. Then this evening I tried the old power supply. I plugged everything in and double checked it, guess what, no crash for 5 straight hours.

Can a loose Peripheral/IDE/SATA modular power cable ause this???

Does this sound like the Power Suppply (in this case my shit install skills) are at fault for the crashes?

The old power supply has a 12V line that read 12.58V in the bios, the new one read 11.9V Should I return the old one for this variance?

Any other thoughts???

 

[UrielDagda]

Did you remember the standoffs and to make sure you didn't screw the mobo in too tightly? Maybe it's touching metal in the case somewhere and shorting out...

 

[Trigeminal]

I definaetely installed the standoffs and no metal was touching the mobo. Seven hours straight with no restart.

 

[BillParrish]

So is the Operating System set to "shutdown" on critical system error or to write an error to the event log and give you a BSOD ? Somewhere in advanced settings in the hardware mamager or thereabout depending on the OS.

 

[Trigeminal]

So is the Operating System set to "shutdown" on critical system error or to write an error to the event log and give you a BSOD ? Somewhere in advanced settings in the hardware mamager or thereabout depending on the OS.

I changed the os to write an error log. It would only wrote the log once, everyother time it simply "shut off".

Now 24 hours with no crash.

 

[Danny Dawg]

I would check all the wires on the old PSU to see if you might have pinched a wire somewhere and it shorted on you. Perhaps a screw penetrated the coating on the wire and caused a short????

 

[Trigeminal]

I would check all the wires on the old PSU to see if you might have pinched a wire somewhere and it shorted on you. Perhaps a screw penetrated the coating on the wire and caused a short????

I actually used the same wires for all tests as this is a fully modular power supply and it was easier/faster to leave them in place.

 

[Trigeminal]

Any thoughts??? Should I return the first PSU??