Like many others, I have been plagued with startup issues (cold boot, restart, etc.) with no obvious solution.
I have a two-year old system based on the DH87MC (AAG74242-401) and an i5-4670K processor. I have a 4-disk RAID-10 array, a DVD drive, and 32 GB of RAM. The power supply is a Seasonic SS-660XP2, and it is on the approved Haswell list. No external graphics, and nothing at all in the PCI or PCIe slots. Running Windows 7-64 bit. No changes in hardware or configuration from the beginning, other than routine Windows updates. Still running the original 0047 BIOS since there was no need to upgrade.
This system has worked flawlessly from the beginning. I do not recall that it has ever crashed or failed in any way. However, over the past few months the startup, either cold or warm, has become sporadic. As noted by many others, when trying to start or restart the power goes on and off, the drive lights flash at times, and the red processor overheat light briefly illuminates. After a few tries everything takes off and works just fine until the next reboot. The problem has become worse and worse by the week.
I have gone through many of the suggestions found on this forum, such as removing the clock battery, playing games with memory slots, etc. Nothing makes any difference. I have reloaded the BIOS, reset to defaults, etc. with no obvious impact.
However, I just discovered a process that appears to work 100% in eliminating this problem. I left the BIOS security jumper off after the last BIOS recovery attempt, and the system boots up perfectly every time. I needed to respond to the screen after the BIOS recovery that I did not want that menu to appear again until the jumper was replaced. The system then boots up just like the good old days.
Obviously the jumper is there for a purpose. I suppose that removing it bypasses some internal checks, such as temperature or voltage limits, in order to have the best chance for system recovery.
So the question is: Will I harm the system by leaving the jumper off (configuration mode)?
Gene