Question Artifacts before POST, but only when boot is set to UEFI

Feb 16, 2021
Hey guys! New member here.


I built a setup yesterday with this configuration:
  • CPU: Ryzen 5 3600
  • PSU: EVGA 500W 80 plus
  • Mobo: ASUS TUF A520 plus
  • RAM: Crucial Ballistix 16 GB RAM 2666 MHz
  • SSD: Kingston A2000 Nvme 250 GB
Considering the GPU's price for now, specially in my country, I decided to stick with my old Powercolor Red dragon RX 460 2GB while saving for a more balance card.

My problem:

When booting the PC, my screen first shows a colored artifact (a blue or pinkiish square surround by vertical lines, exactly likes this RX460 Artifacts - YouTube and this Strange screen upon boot - Microsoft Community ). This screen lasts for 4 or five seconds and, after that, the system starts normally. I don't have any instabilities in the graphics (for now) when use the pc (BIOS and Windows).

After some testing, I found that this problem only occur when CSM is deactivated. If I chose to boot with UEFI + Legacy, the problem don't happen. I tried to disable the logo in POST, but it didn't solve the issue when using only UEFI.

I tested the system with a GT 710 that I have here and with that card I can't see any problem, even when using only UEFI.

For now, looks like a minor thing, but I worried it could be a signal of a more serious issue.

Thank you in advance for your support.
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