Question Is my PSU killing my motherboards?

[veep]

Recently built a PC using new cpu+mb+ram+case+nvme with older hw (PSU, GPU).

My motherboards keep dying and I can't figure out why.
the DRAM error led is on

1st MB died after 1 month.
2nd MB (warranty replacement)- died after 1 day.

Suspect #1: PSU
When I touch the back plate of the GPU I feel a bit of electricity.
The PSU is old, but worked fine on my prior PC a with the same GPU for a year now, and I remember feeling the electricity but it didn't kill anything.

Suspect #2: Case/PSU ground
Could it be maybe the PSU is not grounded to the case very well? I used the screw that came with the case, black screws, the case is also black, maybe there's no good conductivity?

Suspect #3:
Maybe it's the bios. I'm using 4 DIMMS and there's a warning on gigabyte's site:
"Before update BIOS to F40, you have to install EC FW Update Tool (B19.0517.1 or later version) to avoid 4DIMM DDR compatibility on 3rd Gen AMD Ryzen™ CPU. "
That's windows tool, maybe the store negelcted to use it and just updated to the latest bios and somehow using 4 dimms is killing my motherboard?

CPU: Ryzen 3600
MB: Gigabyte B450 Aorus Elite
RAM: 2DIMM 3200 + 2DIMM 3000
GPU: RX580 AORUS
CORSAIR PSU 650W





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[FALC0N]

Well, tell us more about the PSU. Of the three option, it seems like the most plausible. However, there are others. For example, maybe you are shorting the board on a standoff or perhaps you just got unlucky with two defective boards. Static electricity maybe? Are YOU grounded?

 

[veep]

Thanks, what so you mean shorting the board on a standoff? How does that happen? All the standoffs are screwed into, there are no extra standoffs that would touch the board where they shouldn't.
I'm building the pc while being barefoot, no carpet or anything and I also touch the metal case just in case. The A/C in the room is on 20c, can that have anything to do with it (My skin gets dry I think it's the A/C).

 

[jonnyguru]

When I touch the back plate of the GPU I feel a bit of electricity.
The PSU is old, but worked fine on my prior PC a with the same GPU for a year now, and I remember feeling the electricity but it didn't kill anything.

Could it be maybe the PSU is not grounded to the case very well? I used the screw that came with the case, black screws, the case is also black, maybe there's no good conductivity?

Even if the chassis is plastic, the ground is all common through all of the PSU ground wires and back to the PSU. I'm more interested in how you know if your AC outlet is properly grounded? The PSU isn't going to create a floating ground for your PC. It NEEDS an Earth ground for proper operation.

Did you test your AC socket with something like this:

https://www.amazon.com/Electrical-Receptacle-Outlet-Ground-Tester/dp/B0012DHVQ0

???

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