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?