Strange reboot problem

[birthdaymonkey]

I just put together a budget gaming computer using a hand-me-down office machine. (Basically I added a refurbish reference EVGA GTX 660.)

Strangely, while I was stability testing the computer I ran into a puzzling issue - the computer reboots when I'm alt-tabbed out of Unigine Valley Demo. It ran the demo itself all night long without any issue, but as soon as I alt-tabbed again this morning, the machine rebooted right away.

This is reproducible. I haven't seen any instability other than in this specific scenario.

Gigabyte B75M-D3H
Celeron G540
4GB DDR3
GTX 660
Plextor 64GB SSD
Seasonic SS-350 ET 350 watt PSU

Any ideas?

 

[SKORPI0]

Check the settings. Probably that keyboard combo tells it to reboot the system.

 

[VirtualLarry]

Highly unlikely that ALT+TAB is set as a command to reboot the system.

It could be GPU drivers, or it could be RAM or PSU, or even the SSD.

When you ALT+TAB, it puts pressure on the storage and RAM, to page things back in, and when ALT+TABbing a DirectX app back to the foreground, it has to re-acquire DirectX state and memory / resource allocations back from the video drivers.

Have you tried different (older, newer, WHQL, beta) video drivers yet?

Edit: Turn off reboot on BSOD. That way, if it's blue-screening, you'll be able to see the code.

 

[mfenn]

If it's only that one benchmark that causes it to reset, I'd guess drivers. If tabbing out of any game or other 3D application triggers it, then it could still be drivers, but could also be a hardware problem.

Larry's question about what type of reboot you're seeing (hard reset, BSOD, etc.) is very good.

 

[birthdaymonkey]

Figured it out, I think.

Installed and ran Kombustor, which instantly rebooted the machine. So I was now thinking almost certainly PSU. I had assumed the Seasonic would be fine--quality unit with more than enough wattage--but it doesn't have a PCI-E connector so I was using a molex adapter. I expect the PSU just wasn't comfortable with that much wattage running through its molex connectors, which trigged some kind of overcurrent protection.

Anyway, I swapped in a Corsair CX-430 and it runs Kombustor without issue... so I'm cautiously optimistic!

Thanks to all who chimed in. Lesson learned: don't bother with molex-PCIE adapters.

 

[VirtualLarry]

Figured it out, I think.

Thanks to all who chimed in. Lesson learned: don't bother with molex-PCIE adapters.

That's wise advice. I never liked to use them, I would much prefer to purchase a PSU with an adequate number of PCI-E power connectors.

I have used PCI-E power splitters, but I carefully compared the PSU's output on the PCI-E rail to the load being placed on it.

If you must know, it was a Delta-made Antec EarthWatts 650W, which has something like 300W or more on the PCI-E power rail. It was powering a pair of GTX460 1GB OC WindForce cards. It ran, with a Q6600 @ 3.6, for a month straight 24/7 doing Folding@Home on both the CPU + both GPUs, with nary a hiccup.

GREAT PSU!

 

[mfenn]

Figured it out, I think.

Installed and ran Kombustor, which instantly rebooted the machine. So I was now thinking almost certainly PSU. I had assumed the Seasonic would be fine--quality unit with more than enough wattage--but it doesn't have a PCI-E connector so I was using a molex adapter. I expect the PSU just wasn't comfortable with that much wattage running through its molex connectors, which trigged some kind of overcurrent protection.

Anyway, I swapped in a Corsair CX-430 and it runs Kombustor without issue... so I'm cautiously optimistic!

Thanks to all who chimed in. Lesson learned: don't bother with molex-PCIE adapters.

The tricky part about using Molex to PCIe adapters is dealing with a multi-rail design like the SS-350ET (17A + 17A). You have to know which rails the Molex strings are attached to, which may be hard to determine without some trial and error. For example, if the Molex you were using were attached to the same rail as the ATX12V connector, that's only 204W for the CPU and GPU, which is likely not enough.

If you're using single-rail it doesn't matter as they are simply pin adapters and all the power comes from the same source anyway.

At any rate, glad you figured it out!