Question On the edge of killing a second 3060 Ti. Is my PSU faulty?

May 9, 2022

Apologies for posting a duplicate question which was already posted in the graphics card section. However, as I continued troubleshooting my PC, I was wondering if it could be an issue with the PSU, so I post my question here again.

First of all, here are the specs of my PC, which was built three weeks ago.
CPU: AMD Ryzen 7 5700X
Motherboard: ASUS TUF Gaming B550-Plus WIFI II
Ram: Kingston FURY Beast 32GB 3200MHz DDR4 x2
SSD/HDD: WD Black SN850 1TB (OS disk), WD Green SATA M2 240GB (Linux disk), WD Green HDD 1TB (old disk for downloads)
GPU: MSI GeForce RTX 3060 Ti Ventus 2X 8GB OC (dead and replaced), Inno3D GeForce RTX 3060Ti iChill X3 RED LHR 8GB (replacement), ASUS STRIX GeForce GTX 960 4GB (temporary card before replacement)
PSU: Cooler Master MWE Gold v2 750W Modular PSU
Chassis: Kolink Observatory Lite Mesh
OS: Windows 11 Pro
Monitor: AOpen (A sub-brand of Acer) 27HC5R x2, FHD@144Hz, connected via HDMI and DP respectively

Two weeks after building my new PC, one day I played Microsoft Flight Simulator for a while (the MSI 3060 Ti was installed). During the game, the GPU core was between 80-85 degrees. After I stopped the game, the monitor lost the video signal when I was casually browsing the web, Windows was still running and music was still playing even though the monitor went blank. When this first happened, somehow I decided to reset CMOS and I could bring back the graphics card to normal. However, after a week the same happened again. But this time nothing could help, no matter how many times I power-cycle the computer or reset the CMOS or anything. And I noticed that the fault indicators on the motherboard had the VGA light on, so I thought the MSI 3060 Ti card was faulty indeed, and I sent it back to the retailer. They said the card was faulty and issued a refund.

While I was waiting for the inspection, I installed an old GTX960 as a temporary card. It's still good enough for some FHD games, even though it's 5 years old. I was able to play 3D games like Flight Simulator, and Lost Ark, without encountering the above-said problem.

With the refund, I got another 3060 Ti card, this time it's Inno3D GeForce RTX 3060Ti iChill X3 RED LHR 8GB. I installed it back on the PC. Then I opened Lost Ark wanting to make sure the new card is working. Just less than 3 minutes into the game, the same problem happened again - Monitors lost signal, Windows continued running, and audio didn't stop. After power-cycling, the display signals were back, but I turned off the PC and replaced the 3060 Ti with GTX 960 to prevent further damage to the 3060 Ti. Since I have the same problem even with a second 3060 Ti, I would doubt whether the first card was faulty, or some other components might have damaged it - motherboard or PSU as they are the only pieces the graphics card is directly connected to.

If this is due to a faulty motherboard, the GTX 960 should have shown the same problem. But the GTX 960 worked fine instead. Although it's less powerful than 3060 Ti, it could still work at its full load without cutting off the display signal.

Could this indicate that my PSU is faulty? However, the GTX 960 only requires a 6-pin power connector, while the RTX 3060 Ti needs an 8-pin one. So I can't tell if the difference of the 2-pin (meaning more power drawn from the PSU to the graphics card) would trigger an issue with the PSU and cause damage to the graphics card...

Since PSU is not an expensive replacement, I've ordered a Corsair RM650x to see if my current PSU is the culprit. But I'm really scared to install the 3060 Ti again, even with a new PSU... So any suggestions or ideas would be greatly appreciated.