Cold boot issue on am5
Hi everyone,
I'm having a very strange boot issue with my PC and I'm running out of ideas.
My system :
CPU: AMD Ryzen 7 9850X3D
Motherboard: ASUS ROG Strix X870-F Gaming WiFi
RAM: Kingston DDR5 (2×16 GB, EXPO kit)
BIOS updated to the latest version (2401)
Summary of the issue :
I cannot cold boot the system.
Here's exactly what happens :
If I perform a Clear CMOS, the system POSTs correctly.
I get the "Press F1 to run setup" screen.
I can enter the BIOS and use Boot Override to boot into Windows.
Once Windows is running, the PC is 100% stable. I can play games (Forza, etc.) with no crashes or instability.
From Windows, I can restart the PC without any issues.
I can even shut it down for about 10 seconds, power it back on, and it boots normally.
However...
If I leave the PC powered off for about an hour or longer, it will no longer POST.
The motherboard gets stuck with the CPU Q-LED (red) permanently lit (occasionally I've also seen the DRAM LED during troubleshooting, but now it's mostly the CPU LED). No display output, fans spin at full speed.
The only way to recover is to:
Clear CMOS.
Enter BIOS.
Boot Windows via Boot Override.
Then the cycle repeats.
What I've already tried :
Updated the BIOS using USB BIOS FlashBack.
Cleared CMOS multiple times.
Loaded optimized defaults.
Disabled EXPO.
Disabled Fast Boot.
Disabled Memory Context Restore.
Enabled Power Down.
Reseated the RAM.
Disconnected all unnecessary USB devices.
None of these fixed the issue.
Has anyone experienced something similar on AM5 or with the ASUS X870 series?
At this point, I'm wondering if this is a motherboard issue, a BIOS/UEFI issue, or something related to the CPU's memory controller.
Any ideas would be greatly appreciated.
Additional information:
About a month ago, the PC was running perfectly and was completely stable.
I had experienced cold boot issues in the past, but they were resolved by using the correct BIOS settings—specifically enabling EXPO II instead of EXPO I. After that, the system had been running flawlessly for several months.
I then went on vacation for three weeks. During that time, the PC remained powered off but still plugged into mains power.
When I came back, this issue appeared for the first time. We believe there was at least one power outage caused by a thunderstorm while we were away.
However, the house has a recent electrical installation with proper protection, so I wouldn't expect that alone to have damaged any hardware.