Isolating an intermittent boot issue..

[BruceG87]

So I've run into a rather odd boot issue recently. A friend has come to me with a relatively new built PC that is suffering from an odd boot issue.

It runs fine for the most part, but every other day it fails to boot properly.

Upon failing to boot properly, it defaults to the BIOS screen, upon exiting that it starts into a reboot loop before ending on the following screen, and from there it appears to be a coin flip on if it will successfully boot or fail to do so and end on this screen. Finally, this issue only happens on initial boot. After asking, it seems that upon successful boot into windows there are no further issues.

The problem is, this issue is so intermittent that since the computer was brought to me I have been unable to duplicate it at all. I pulled the PSU, shorted it, put it under load via a fan and tested it only to find no issue. I tested the memory in every possible config, dual and single, and found zero issues. Just for good measure, I put the PC under a few stress tests to force some heat and see if there was any other instability. After all my effort, I still have nothing.

So here I am, open to any input or suggestions.

EDIT
System Specs are as follow

Intel G1610
ASRock H61MV-ITX
Mushkin Essentials PC3L-12800 (2x4GB)
Allied AL8250SFX 250 Watt (Generic PSU that came with case, but again it tested fine without any issue)
Samsung 840 EVO 120GB

[acphydro]

I would re-seat all connections [power, add in cards etc]. It's most likely a memory related issue [bios settings for timings or voltage], cpu voltage related on boot or power supply. Generic PSU would be first thing I'd replace after all that, regardless of how it tested, it could run fine one boot and not the next, I'm betting the regulation is all over the place and causing the intermittent issue.

[BruceG87]

I would re-seat all connections [power, add in cards etc]. It's most likely a memory related issue [bios settings for timings or voltage], cpu voltage related on boot or power supply. Generic PSU would be first thing I'd replace after all that, regardless of how it tested, it could run fine one boot and not the next, I'm betting the regulation is all over the place and causing the intermittent issue.

One of the first things I did was completely reseat everything.

Additionally, I tested the memory in every config not only with that hardware, but in a second rig as well.

I tested the power supply at varying levels of load and it was nothing but consistent.

[acphydro]

One of the first things I did was completely reseat everything.

Additionally, I tested the memory in every config not only with that hardware, but in a second rig as well.

I tested the power supply at varying levels of load and it was nothing but consistent.

If the memory has been tested and is on the board vendor's list it's probably good. Have you tried relaxing all timings and ensure everything is set to stock?. It's still very possible it's memory or CPU voltage related, if the volts are just a hair off that could cause stability issues like during boot intermittently. I assume you also resealed the processor as well then?

You could check for a bios update or load bios defaults or increase voltage for CPU and ram a hair if the board allows it. Dirty power could also cause that issue. Either way I'd still suspect the PSU regardless of it being tested. Intermittent issues do suck. I bet if you could test with another PSU you'd likely find the issue gone. You could try testing a different GPU but likely not issue.

Either way, good luck.

Edit: Just wanted to add you could try a CMOS battery swap as well.

[Lathais]

I tested the power supply at varying levels of load and it was nothing but consistent.

That's the thing with intermittent problems. They are intermittent and not showing their ugly head while you are testing. I'd suspect the PSU as well.

[BruceG87]

That's the thing with intermittent problems. They are intermittent and not showing their ugly head while you are testing. I'd suspect the PSU as well.

Here is my issue, with me being unable to replicate said issue.. I simply can not recommend any money spent without guaranteeing that money will resolve the issue.. and frankly, it's bad troubleshooting technique to implement a fix without isolating the issue from the start.

[Amorac]

Even intermittent have some form of timeframe or occurence frequency. Once a week/month/year, every 111th boot time, every 23 days, 23 hours, 11 minutes etc etc. How long have you had the PC for testing.

Since you reseat everything you could have fixed it allready. Testing it if it only had the problem once a month will be impossible. External influences may also affect it.

[acphydro]

Did you try a different GPU? Your didn't mention what GPU was being used.

If you have and came to no conclusion, I'd give it back and ask your friend to take notice if it only happens during a brownout, after a surge, or sudden power loss. Some boards overcurrent protection kick in after that scenario. Failing that I'd still suspect PSU and would at least swap in a known good one. Unfortunately this is one of those intermittent problems that could be very hard to nail down with time playing the troubleshoot factor and not knowledge.