3

When a PC with more than one GPU installed boots, how does it determine which display adapter to use for the boot display when you have more than one GPU?

And how to specify which gpu to use for display?

tinus
  • 31
  • 1
  • 4

1 Answers1

10

This is entirely up to the BIOS. Generally, it will select any onboard graphics first. Some will detect if a graphics card was inserted and default to its first display. I believe if more than one graphics card is inserted, it will default to the first display on the first card. However, sometimes Ive seen in display on whatever output has a monitor attached to it... Which means the graphics cards can affect the display.

I dont think there is one answer that fits every situation.

Keltari
  • 71,875
  • 26
  • 179
  • 229
  • 4
    Another option I've seen is to output to all displays. – trlkly Feb 13 '23 at 06:07
  • 1
    I've seen some systems with both CPU-gfx and dedicated GPU were in EFI mode the GPU handled teh display and in EFI/CSM mode the CPU's internal GPU got the display. Serious WTF moment when you switch the EFI/CSM mode. My intern thought he had broken the PC when he lost display after enabling the CSM. – Tonny Feb 13 '23 at 14:18
  • I've often seen a setting in BIOS about which GPU to use. At least choosing between integrated and discrete (haven't had a system with multiple discrete GPUs). – Vilx- Feb 13 '23 at 22:41