Question Replacing CPU - PC Won't Start

[EpicPenguin09]

Hi,

I've replaced the CPU in my PC, however once installed and the power button is pressed, the PC starts up for about half a second, then clicks back off again (doesn't make it to POST). It tries to start again a couple of seconds later and the cycle repeats. If anyone could offer advice it would be much appreciated! I've tried updating the BIOS (version & motherboard listed as compatible with the new CPU on the Intel website), resetting the CMOS, checking for bent socket pins (there are none) and removing a stick of RAM. If I re-install the old CPU, the PC starts up with no issues.

Specs:

Intel 5820K - Old CPU being replaced
Intel 6950X - New CPU
Asus X99 Deluxe - motherboard (BIOS version 4101)
Crucial Ballistix 8Gb DDR4 (2400MHz) x2 - RAM
Gigabyte GeForce RTX3070 Eagle - GPU
Corsair H100i - CPU cooler (water cooled)
Corsair HX850i PSU

As far as I can see, everything should be compatible. I had been sent one 6950X from one supplier, however upon arrival and installation it was producing a weird buzzing noise (coming from the CPU itself and not the cooler or any other fan), which was fairly odd. Looking around it seems this one was dead. I then purchased a refurbished & tested CPU (which does have a warranty, so if it seems the CPU is dead I can go back to them), which is the one that's causing the above issues.

Any advice would be great! Happy to provide further info if needed.

Cheers.

 

[punkncat]

After the first issue, did you put the original CPU back in and see that the system was operating normally?

Support for that CPU should have been 3004 and above. I didn't take the time to read closely, but was there any bridge BIOS that had to be installed before continuing with later revisions? IE, when you updated the BIOS did you do each one in order or just the latest?

 

[EpicPenguin09]

Hi punkncat, thanks for the response.

Yep, after the first occurrence I popped the old CPU back in and the PC works normally. Have tried few times since and after the issue occurring repeatedly, it will still work normally with the old CPU.

I already had the latest BIOS revision flashed and have had for the last few years, so it didn't actually need updating but I thought re-flashing may have helped. I guess there's no benefit it trying to install a slightly older BIOS revision?

Thanks!

 

[EpicPenguin09]

Sorry, should have also added in my first post - I've been cleaning & applying new thermal paste to the CPU with each attempt, so there shouldn't be any overheating issues (not that I'd expect that to cause an issue so quickly anyway)

 

[punkncat]

I am not sure you can go back to an older version of BIOS.

I am not terribly familiar with the chipset, but of thought to consider. Before taking out the old CPU are you resetting CMOS to factory settings. I would assume this board allows XMP and such.

 

[EpicPenguin09]

No worries, it's definitely an older one! I am yep and it does allow XMP and the like.

It may well just be that this CPU is also toast, but just want to make sure there's nothing obviously wrong with my system/methods before I return! Seems a bit odd to receive two dead ones from two different places, but it might be the case.