No POST issue, solved, maybe...

[sb4ssman]

Asus Z170 Pro Gaming

i7 6700k

Cosair hsomething AIO

Samsung 950 Pro boot drive

A pair of Sumsung SSDs in Raid 0

Seagate spinning rust

2x Gtx 1080 sli

EVGA 750w gold plus PSU

 

I began having boot trouble a week or three ago. I've had the computer for several years, built it and regularly maintained and cleaned it. It's been working great for a long time. Until recently, when only the PSU would power on with the power button. 

 

The mobo lights are on like normal, and the power button seemed to have no other effect than to fire up the PSU which appeared to be working normally, just nothing else happened. Actually the spinning hard drive would make some noise, but no lights on the cooler, no fans spinning, no beeps, and none of the boot status lights on the mobo. 

 

The kicker, is that it was not always. After a couple tries, sometimes it would just work, and once it was ON, there was no trouble, no random restarts, no crashes, it could run all day for work and gaming and there would be no indication of any issue once I got the machine turned on. 

 

It slowly got worse, and no amount of reseating plugs nor components seemed to have any consistent effect. At one point I was convinced the power or reset buttons were shorting it, but booting results were just as inconsistent as before I tinkered with them. 

 

Yesterday I could not get it to boot at all. Fully tore it apart, cleaned anything I could, reseated plugs multiple times, and still had inconsistent boot results. Something around 1 in 10 to 20 successful boots, and things were FINE if I got it booted. I was able to update things and restart, double check my BIOS was up to date, push the machine to it's limits with gaming with overclocks, etc, but only when the original boot worked. If I ever turned it off, there was that big chance it would fail to boot again. 

 

Eventually fussing about with things it appeared the CPU wasn't getting power, so switched the CPU power cable from the PSU-CPU1 rail to CPU2. SO FAR, I have been booting reliably. I did lose my RAID volume swapping the button cell battery during troubleshooting, but it was just game data, so beyond the hassle of reconfiguring the volume and re-downloading, that was OK. 

 

At this point, is there any risk to my system using the secondary CPU power rail? Is it normal for a single rail to die in a PSU? Could it have anything to do with an overclock that burned out the power rail? (Extremely stable at 4.6ghz for many years now, but I never messed with anything but the multiplier). I ask because I'd rather boost it back up but I'm running stock clocks for now. 

 

Does anyone have any deeper insight into my situation, any ideas about any fringe case weird scenarios that might have caused my boot problems, or if I should immediately shop around for a new PSU and begin the process of Ship-of-Theseus-ing my rig?