Follow-up Q is at Computer restarts randomly - all parts A/B tested
So, I have this system which has a Gigabyte H97 board with an i5 CPU and 2x 4GB Corsair DDR3-1600 sticks. Two HDDs - Windows 7 on the WD and OpenSuSE Linux on the Seagate.
Background: One day in June, it wouldn't resume from sleep into Win 7. Case buttons didn't do anything, shorting the power pins didn't work either. Sent MoBo to dealer who sent it to Gigabyte.
When returned, it worked but with one quirk. The 2nd HDD - Seagate - would occasionally disappear in Win i.e. the drive letters would vanish. Disabling and re-enabling the relevant ATA channel in Device Manager would restore drive visibility. There was no data corruption on that drive. SMART indicators looked normal in Speedfan. This happened, maybe 3-4 times, within a few weeks of return and then stopped. When booted into Linux, it would never freeze as if the drive had died or was missing. This problem never occurred with the first (WD) drive.
Current problem: One day in mid-October, shortly after resuming from sleep, the system suddenly restarted. There was negligible CPU load at the time. Once back in Windows, I checked the system events, and spotted
The system has rebooted without cleanly shutting down first. This error could be caused if the system stopped responding, crashed, or lost power unexpectedly.
There were no other event messages that threw light on what had happened.
It happened again the next day. Thrice. I ran the Windows 7 memory diagnostics tool available from the boot menu and ran the two passes. No errors reported. The next restart happened three days later. The one after that two days later. I called my dealer to take a look. On the day before he took it, it happened four times. Twice while in linux; once while in the BIOS. He took the whole case, minus the drives. He was able to reproduce the behaviour at his office with his Win 7 HDD. So he moved the MoBo along with my CPU/RAM to another case and PSU. After a day and a half, there were no restarts, so he inferred the problem was with either my PSU or case - both Corsair.
I brought back the system - my MoBo in his case + PSU - to test for a few days. About 15 minutes after reconnecting my drives and booting into Windows, it restarted. I decided to keep it for a few days to see if the frequency of restarts had changed. Now, the old problem reared its head again. The 2nd HDD's drive letters disappeared but this time cycling the ATA channel didn't work. I rebooted into the BIOS and the drive wasn't visible. I shut down the system and checked the data & power cables. The drive reappeared and I booted into Linux normally. The data seemed fine. Back into Windows, the SMART indicators still reported no errors.
Over the next week, the system restarted once. The drive disappeared once, and so I switched the SATA port to which it was connected. Again, the drive functioned normally for a few days before it disappeared again. Cycling the ATA channel didn't help. It didn't show up in BIOS either, but I decided to try to POST again by changing some inconsequential setting in the BIOS (actually UEFI). The 2nd drive's EFI entry showed up in the boot menu and I could boot into Linux. During all my Linux sessions, this 2nd HDD never 'disappeared' or froze.
Then the system resumed the spontaneous restarting with some frequency - ~2x in 3 days. So I decided to get it sent for repair (yes, yes .. why the hurry?). My dealer sent it to them - just the Mobo - a week ago.
I spoke to the Gigabyte service centre today who have given a clean bill of health to the MoBo, saying that they ran a 'burn-in' test for two days and have found no issues.
Hence, my question: what do I tell them to look for, in order to reproduce the behaviour? They have suggested that if I send across my CPU+RAM, they can test with that combo. I may do that, but is there anything specific I can ask them to test?.
Thanks for the patience.