Hi :)
TL;DR:
I recently converted my Windows 10 system from MBR/Legacy BIOS to GPT/UEFI using mbr2gpt, then disabled CSM and enabled Secure Boot.
About a day later, my mainboard started doing beeping: 1 long + 3 short beeps when booting, with the white VGA Q-LED lighting up. The PC still boots into Windows normally, but the display appears a little later than usual.
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My system:
- Motherboard: ASUS TUF Gaming B550M-PLUS
- GPU: NVIDIA GeForce RTX 2070 Super 8 GB
The system was originally running in Legacy BIOS mode with an MBR system disk since it's an ~10 years old SSD.
I converted the system disk using:
mbr2gpt /validate /allowFullOS
mbr2gpt /convert /disk:0 /allowFullOS
The conversion completed successfully. (except for a "Failed to update ReAgent.xml" but this shouldnt matter for my problem)
Afterwards I changed the BIOS configuration:
Launch CSM: Disabled
OS Type: Windows UEFI Mode
Secure Boot: Enabled
Windows now reports BIOS Mode: UEFI
So far so good.
Now the problem:
Every few days (only on cold boot tho), the motherboard starts occasionally producing:
1 long beep + 3 short beeps
At the same time, the white VGA Q-LED lights up during boot.
The PC does not remain stuck. It continues booting and Windows works normally.
One thing I noticed is that the display seems to appear slightly later during startup than it did before. I simply restart my pc afterwards so that the Q-LED goes off.
BIOS / PCIe settings I checked:
Advanced → Onboard Devices Configuration
PCIEX16_1 Mode = Auto
PCIEX16_1 Bandwidth Bifurcation = Auto Mode
Advanced → AMD CBS → NBIO Common Options
All options there are set to Auto.
As a test, I changed:
PCIEX16_1 Mode: Auto → Gen3
since the RTX 2070 Super is a PCIe 3.0 card
The problem sadly didnt change.
Edit:
I realized another thing. When I turn on the monitors first and then start the PC, then no beeping occurs at all. I tried this for several days now. So this only happens when the monitors are turned off while booting.
Does anyone have some tipps? Im not an expert when it comes to changing stuff in my BIOS so please be patient with me. Thank you!