Houston, We Have A Problem!
For a long time, all my computers had been configured to go into sleep mode instead of shutting down normally. It is very convenient because it greatly reduces wasted boot time. And when the usual power supply problems began in the morning, the equipment was “off,” and I was calm. As it turned out, a little too calm. In the evening, after trying to turn on the computer, I discovered what the internet calls a “reboot loop,” a cycle of reboots that is a very well-known problem with Gigabyte motherboards, and also with some others on the Sandy Bridge platform.
And what exactly is this problem? After being powered on, the computer runs for several seconds, spins up the coolers, blinks its lights, but shuts down before reaching POST. A few more seconds of silence pass, and it starts again, only to end this attempt just as ingloriously. And that is the whole cycle; it can continue indefinitely, without the slightest progress.
System Configuration
- Intel Core i7-2600K processor (3.40 GHz, 4x256 KB, 8 MB, EM64T, GPU), Socket 1155
- Gigabyte GA-P67A-UD3 motherboard (iP67, 4xDDR3, 2xPCI-E, SB, USB 3.0, ATX), rev 1.0
- Memory: 2x DDR3 SDRAM Kingston “HyperX” KHX1600C9D3K2/4GX (PC12800, 1600 MHz, CL9)
Problems Need To Be Solved
I will explain right away: this problem can arise for quite different reasons, from enabled PLL Overvoltage (used for overclocking, present only in experimental firmware for this board) to incorrectly set memory parameters. And it is by no means certain that the solution that helped me can help someone else. But what if? :)
In fact, mine was exactly the second case. As far as I understood, after a broken sleep mode, the system cannot synchronize its work with the memory, and the culprit is most likely Intel microcode. But let us not get ahead of ourselves; the problem needs to be solved step by step. To begin with, you need to reset CMOS in order to get to the BIOS settings at all. Take out the battery and do not touch anything for a while. The ideal option is also to remove all extra memory and leave one stick. After 10-20 minutes, put the battery back in, but not the memory, and start the machine. The reboot loop should already disappear at this stage, but the problem is not solved yet, because only one memory stick is installed. And as soon as all four are put back, the reboot loop returns. What to do!?
To begin with, the BIOS needs to be flashed to a later version. I went to the manufacturer’s site and discovered that my F3 firmware version was not there at all, while the earliest one, F4, was accompanied by a comment saying that our villain, the microcode, had been fixed there. Carefully reflash, following the guide.