Question Motherboard frying RAM?

[exm]

Hi all,
Let me start off with stating that I have been building PC since the early 90s. I'm a hobbyist who has done this before and has troubleshoot many issues. But this one is strange.
Here's the situation: up until a week ago I had a perfectly working build (build app 3 months ago):

• New case, New Seasonic 750W PSU
• Asus Z790 Prime motherboard
• Intel i9-12900K CPU
• G.Skill 2x16 DDR5 Memory
• 1 Tb NVME
• A770 16Gb GPU

Everything was working fine, no issues, no complaint.
However...
I decided to sell my Intel GPU since I don't game a lot, and I figured I might as well wait for Battlemage. So I shutdown Windows, turned the PSU power switch to off, unplugged from power, unplugged all other cables and remove the A770. I never disabled the internal CPU GPU. Pretty straight-forward, right?
However, after turning my computer back on (HDMI cable in the mobo HDMI-out), the computer turns on, no picture. Strange. So I tried all the troubleshooting you can think of:

• Second monitor. Monitor on/off
• Plug the A770 back in, see if that one works
• CMOS reset, removing CMOS battery to do a BIOS reset

Nothing worked. So out of desperation, I figured, the mobo is somehow fried. So I bought the ASROCK Z790 Riptide Wifi (better specs anyway). Re-installed everything, same problem. Okay, so next: stop to Microcenter. The helpdesk wasn't really helpful but at least the tried to boot the computer, same problem. So I walked out with a new i9-12900K and a new set of DDR5 memory to troubleshoot (15 days returns, I spoke with the guys there and they were cool with it).
I booted my computer with the new ASROCK motherboard, and the new memory and voila, the computer turned on! Hurray, bad memory! But wait, I'm not done.
So I figured to see what happened with the old ASUS motherboard:

• Reinstalled the old motherboard, with the new memory. Same issue again. No picture. Oh man, motherboard+memory issue?

Here comes the kicker:

• When I re-installed the ASROCK motherboard with the new memory (the setup that just worked), it's not working now. NO PICTURE!
• So I figured to swap the Intel CPU for the NIB I have here. NO PICTURE.

My theory, the only working theory I can think of, is that the Asus motherboard somehow fries the memory. I have another pair of memory ordered (this time from Amazon) to try out this theory. Does this makes sense at all? Any other thoughts (I was thinking PSU, but it's a brand new Seasonic PSU that's working fine and everything seems to be powering on)?
Glad to hear your thoughts.
(and yes, I tried dual channel and single channel memory configurations above)

 

[Ralston18]

This motherboard?

https://dlcdnets.asus.com/pub/ASUS/...26_PRIME_Z790-P_UM_WEB.pdf?model=PRIME Z790-P

 

[exm]

This motherboard?

https://dlcdnets.asus.com/pub/ASUS/mb/LGA1700/PRIME_Z790-P/E20426_PRIME_Z790-P_UM_WEB.pdf?model=PRIME Z790-P

Yes. The “WiFi” variant of the “p”.

 

[Ralston18]

When CMOS was cleared (Page 1-16) of the User Manual is BIOS accessible via the DEL key? (Also refer to Pag3-2.)

Any beep codes at startup per Page 2-20?

My suggestion is a very careful re-read of the User Manual. First to ensure that all installed components are supported and correctly configured. Check the manufacturer's website for any updates or changes not in the User Manual.

Second work through the entire User manual to verify that all connectors, cards, RAM, jumpers, and case connections are fully and firmly in place. Read all fine print and warnings/cautions.

Third while doing so use a bright flashlight to inspect everything and everywhere for signs of damage, corrosion, cracks, pinched/kinked wires, missing or loose screws.

If possible swap in another known working PSU - remember to use only the cables that come with the swapped in PSU.

 

[exm]

When CMOS was cleared (Page 1-16) of the User Manual is BIOS accessible via the DEL key? (Also refer to Pag3-2.)

Any beep codes at startup per Page 2-20?

My suggestion is a very careful re-read of the User Manual. First to ensure that all installed components are supported and correctly configured. Check the manufacturer's website for any updates or changes not in the User Manual.

Second work through the entire User manual to verify that all connectors, cards, RAM, jumpers, and case connections are fully and firmly in place. Read all fine print and warnings/cautions.

Third while doing so use a bright flashlight to inspect everything and everywhere for signs of damage, corrosion, cracks, pinched/kinked wires, missing or loose screws.

If possible swap in another known working PSU - remember to use only the cables that come with the swapped in PSU.

Thanks for the reply. With the Asus motherboards, the power light was flashing. No beeps. Google search hinted at the CMOS clear which is what I did.

I also tried to run the computer with only the minimal connectors connected. I'm expecting another pair of RAM today. If that doesn't resolve the problem, I'll have to check the PSU.