Ladies + Gentlemen,
yes a hammer would do. But unfortunately it is more complicated.
1st i7-4790K: system built 2014, system was stable, went dark mid 2018 during Windows update/reboot, no beep, no BIOS anymore, just switching on and off permanently with a dark screen. Never overclocked, CPU internal graphic only (programming PC- not for gaming). MB Asus Z97-A: red CPU warning light is on almost immediately after Power on.
HW: PSU: beQuiet 500W, MB: Asus Z97-A, Cooler bequiet Black Rock (almost not fitting in the case)
Final summary: CPU damaged, MB damaged, PSU damaged and replaced by supplier (within 5years warranty)
2nd i7-4790K, 10/2018:
exchanged, new: PSU: Corsair CM 750W, MB Supero C7Z97, 2nd i7-4790K. Cooler: the same, RAM the same, system was stable.
and again: 10/2019 went dark during Windows update/reboot, no beep, no BIOS anymore, just switching on and off permanently with a dark screen. Never overclocked, this time external graphic (2070), different screens too.
But this system is now running again with my spare i3-4160 and seems stable so far.
A POST test card is on the way.
Questions to the forum:
1) What is the difference from i3-4160 to i7-4790K in terms of pinning? Are there some CPU pins/contacts unused at i3?
2) How would overtemp signs look like? I would have expected a warning (the Supero can beep and has a LED for that) and then a shutdown- but of course I did not watch exactly at this moment- I could not reproduce any warning with the already damaged CPU. Since both i7 did not collapse under heavy load can I exclude that?
3) I exchanged/rotated/removed all RAM modules (4x8GB), no change. Can a RAM cause such a behaviour?
Do I have 2 different reasons here with the same behaviour and just bad luck? Or did I miss something?
If you have any suggestion or idea please reply.
Only difference between these two processors is the obvious performance differences and their power consumption. Physically, they use the same memory buses, same DMI connection to the chipset, etc. and etc.
These sound more like board or BIOS issues as opposed to processor issues. Have you tried that i3 in the first board as well?
Thanks! The first MB Z97-A is really dead, the i3 was purchased to test exactly this. BIOS is always latest ( I am a kind of an update-freak) , though that does not mean it covers all problems.
My assumption for the first system is that the PSU damaged MB and CPU.
Before I exchange the i3 to a faster one (it can't do the job), I would like to find out what happened to the second i7.
So you verified that the first motherboard is not working correctly. Based upon your description, thoough, this sounds like BIOS corruption, not that anything was physically damaged. Have you tried this i7 processor in the other board?
I tried this recently, before finalizing my conclusions over the second i7 and with a small glimpse of hope it might somehow work:
No, both i7 are dead, the first MB Z97A shows no signs of life (even with the well working i3-that was known).
The second system with Supermicro MB+ i3 is still ok and working.
The plan is now to wait for the POST Test card and analyse the outcome in a direct comparison between a working and a damaged system/combinations of it.