Computer shutdown. No BSOD

This is my wife computer.
In September 2013 I bought a Gigabyte Z87-D3HP MoBo and a i5 4760K intel CPU at Microcenter and a (4+4)G Team DDR3 – 2400 - (Cl 10-11-11-31) - 1.65V from Newegg.
I had some issues with the MoBo. It didn’t always recognize the HDD. I’ve tried to update the BIOS, change SATA cables and connectors. A month later I went back to Microcenter and they replaced the MB. Just filled up a form informing the problem with the MoBo. I was very happy with Microcenter.

It ran normally for almost 4 years with a light (10%) CPU overclock. Turbo boost multiplier was set as 42 instead of 38.
Last April the computer began to randomly shutdown. No BSOD. Then it used to boot normally (after a check disk). It could run for days without a shutdown. The shutdown began to happen more frequently.

Then it died. Couldn’t boot. I tested the memories on another computer and found no problems. I cleaned the memory slots, the CPU and sprayed the CPU slot with a contact cleaner and reset BIOS. For my surprise it booted. When I was configuring BIOS it shut ed down. After some minutes, it booted again. Then I noticed that the max turbo boost multiplier was reported as 36 when it should be 38. Then I changed the default multiplier from 34 to 25 (normal and boost) and set the base clock from 100MHz to 80MHz.
CPU was working with 2G at 32ºC, chipset with 80MHz at 28ºC and still shutting down. Nothing happens if I tried to reboot. I have to switch the power supply off, wait for ½ a minute and then try to boot. Sometimes it boots, sometimes it beeps continuously.

Unfortunately I don’t have another 1150 CPU or motherboard to find out if the problem is on the CPU or on the MB. I’m quite sure isn’t on the memories, as it worked on the other MB.

Any ideas?

Have you checked the PSU. It's surprising how often a sluggish PSU can cause weird problems.

Since I NEVER use Intel CPU's, I'm always suspicious of them when weird and misc. problems are reported. For instance, they have been known to be much more heat sensitive than, say an AMD cpu.

Have you removed the CPU heatsink from the CPU Chip and cleaned it thoroughly, and then reinstalled it with new heat sink grease?

I did a tutorial years ago on the subject of 'Washing RAM'. I've saved many sticks of ram that maybe didn't check bad on a Memtest, but still caused a PC to fail under heavy loads. I submerse the ram stick in a shallow tray, filled with Denatured Alcohol, and I scrub it with an old toothbrush, concentrating on the little legs of the ram chips. Dirt particles that we can't even see, between the legs of the chips, can cause them to short out and fail and it can be intermittent. Even chips that do fail Memtest, can often times be recovered by a good washing and thorough drying, before reinstalling into the PC.

The final step in most PC board manufacture is a thorough washing in a detergent, followed by a rinse in de-ionized water. I used to do all the PC board prototyping for CAT, so I do have some experience in that area.

If you lived a bit closer to Florida, I'd ask you to bring that PC over here and let me have a look at it.
Troubleshooting problems over the phone or the internet is really quite difficult.

Good Luck Mate!
TechnoMage

Congratulations!
You finally got it fixed, and in only three years, more or less. Sounds like something I might do.


Good Luck Mate!