ASUS ROG STRIX Z390-F GAMING - PC restarting itself automatically on boot

[-Gaia-]

Hello everybody I'm new here and I hope you can help me

4 years ago I built my PC, it’s not overclocked and I use it mainly for 3D, graphic and video works and a bit for gaming. Here the specs:

PSU: Seasonic PRIME Platinum 750W
MB: ASUS ROG STRIX Z390-F GAMING (BIOS v1802)
CPU: Intel Core i7-9700K 3,6 GHz - cooling Corsair Hydro H115i PRO
RAM: Crucial Ballistix Sport LT DDR4 2666 MHz ‎1,2 Volt - 16GB x4
GPU: ZOTAC GeForce GTX 1070 8GB AMP! Extreme Edition
Drives: Samsung 980 PRO PCIe NVMe M.2 500GB - for boot drive, Samsung 860 EVO SSD SATA III 250 GB, Samsung 850 EVO SSD SATA III 250 GB, Seagate Barracuda Pro SATA III 6TB
OS: Windows 10 pro x64

Some days ago it stopped working: when I turn it on, it restarts 3 times and then doesn’t boot the OS. After the 3 restarts it shows this screen

BIOS now has default settings, so it doesn't see the M2 system boot disk. When I enable CSM it starts Windows, but then if I turn it off it loses this setting again.

I didn’t change anything before this issue, didn't even update Windows or drivers last time I used it.

I first thought it could be a RAM issue because it is restarting when the RAM LED on MoBo is on, but I tried to use each RAM module alone and the PC restarted every time exactly in the same way. Here a video:
https://youtu.be/kk86aeRFC-k
I also launched Windows Memory Diagnostics Tool, result is “no error”.

Now I am afraid it may be a MoBo issue, how can I check it?
What do you advise me to do? Let me know if more details are needed

[Nate152]

Hi Gaia

Welcome to the ROG forum.

After enabling CSM, did you press the F10 key to save the setting?

When you installed windows, did you do a UEFI install?

The bios screen is usually a sign of instability, since you're not overclocking, I suspect unstable ram even though it passed windows diagnostics.

Is your ram a single 64GB kit or are you combining sticks?

All good at default settings?

When you set your ram try raising:

1) Dram voltage - 1.35v
2) CPU VCCIO voltage - 1.25v
3) CPU System Agent voltage - 1.25v

F10 and Enter to save and exit.

How does it go?

[-Gaia-]

Hi Nate, thank you for answering

After enabling CSM, did you press the F10 key to save the setting?

Yes, I saved. I checked it again: it doesn't restart and it keeps the CSM enabled if I reboot or turn off the system, but it restarts and loses the setting when I unplug the power. I checked the PSU's voltages, everything is fine.

When you installed windows, did you do a UEFI install?

I don't remember that, it's been too long. Anyway I checked the System Information App and it says it's in Legacy mode. Is it a problem?

Is your ram a single 64GB kit or are you combining sticks?

I have 4 sticks, 16GB each. They are from 2 different sets of the same product, and I paid attention to put them paired in the correct slots.

All good at default settings?

I think yes, settings look ok with hardware specs.

I'm sorry but there are a lot of things that I don't know about in the BIOS. I always used it in default mode, except for enabling CSM and turning off aura leds.