Sign up ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I built a new computer two months ago:

  • Motherboard: ASUS H87-Pro
  • Processor: i5-4570
  • Memory: Vengeance LP - 2x 4 Go - PC12800 - 1600 MHz - CL9 - CML8GX3M2A1600C9 in slots A2 and B2.
  • Case: Advance Monster
  • Hard drive: WD Blue Caviar 500G
  • PSU: Corsair CX500M

I began to experience a strange problem ~3 weeks after the assembly. When I first turn on the computer just after connecting the power outlet, the computer runs fine. When I turn on the computer a few minutes after turning it off, the computer runs fine. But if I turn on the computer more than ~20minutes after turning it off, it begins a sequence of quick "reboot loop", more or less longer before starting the OS: the computer begins to start (the fans start, the MemOK LED flashes once as usually) and then the computer stops (not always after the same duration) and starts again... Until a successful start (that I first noticed with the usual beep).

When the computer gets to start the operating system, it is stable: I can use 100% of the resources for several hours without any concern.

The problem persists with:

  • only one memory slot in A1 which passes the memtest.
  • another PSU.
  • without any PCI extension card.
  • without hard drive or optical drive.
  • older or newest BIOS.
  • Clear RTC using pins on the motherboard.

I begin to think it's a manufacturing bug in this motherboard but I find it strange that the system is stable when it arrives to start and that I can power on the computer without any issue when it was just shut down (maybe a capacitor problem?).

Do you have any idea? Something I forgot? If it is the motherboard, how to explain these symptoms?


share|improve this question
Clean all the RAM and PCIe connectors with contact spray. Also reseat the memory, just take it out and reinstall in another slot. Check the 12V CPU connector – Nikola Dimitrijevic Oct 6 '13 at 0:29
Do no spray or clean anything! Unless you want to damage your PC or void your warranty. In this situation its best to make sure you have the latest BIOS/firmware/drivers. Check the manufacturers websites to see if their are any updates. – Keltari Dec 2 '13 at 4:29

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.