Question BSOD with stock speed

[rvthz]

I recently bought a second hand i3-6100. The previous owner said that it only works at 3.3GHz speed and i have to underclock it. When put the CPU in my PC it worked perfectly fine on stock 3.7Ghz for 5 days, day 6 after updating all drivers I started getting CPU-related BSOD's. After underclocking it to 3.3GHz as the previous owner said it is working perfectly fine. I restored my system to before I installed the drivers but it didn't help.

What could be the problem? Is it fixable?

 

[helpstar]

Which BSODs came up?

Did you only buy the 6100 or was it sold with a motherboard?

Is the motherboard´s BIOS up to date?
Which motherboard is it?

How hot is the CPU?

 

[rvthz]

The BSOD says MACHINE_CHECK_EXCEPTION.

I bought just the i3, my motherboard is MSI z170a gaming M3, I haven't updated the BIOS.

The CPU temps are the same as i got with my old i5-6600k, around 40°C

Update: I just ran an OCCT test on 3.3GHz and after few minutes I got BSOD: CLOCK_WATCHDOG_TIMEOUT

 

[Rdslw]

MACHINE_CHECK_EXCEPTION happens if you have physical checks failed like ones that stops cpu from posting.
I think that cpu was fried & recovered, that's the path I've seen it happen.
basically someone used the cpu for a while and paste was only on half of the cpu or not even applied.

Disable the turbo at least for now. (it does not even have turbo)
as this is the non-k unit, its hard to make cpu consistently underclocked.
0.8V you can go in order to have a stable idling CPU at 800MHz.
Check voltages, you can propably do 0.7V idle and 1.0V at load to make that cpu more stable, with clock close to 3.0-3.1.
But IMHO that cpu should be treated as temporary solution if my initial thesis about "origins" are right. It will get worse and worse, hopefully slowly.

 

[rvthz]

Underclocked to 3.1, got another BSOD when watching YouTube.
Any ideas why the CPU went from working perfectly fine for 5 days and then this happens?