I was reading about the specification of AM5 processors, like the Ryzen 7 7700 and I've noticed that on the specification the internal GPU is available only on UEFI mode and not in Legacy BIOS mode. That meas if I boot a Memtest86+ or Freedos disk to make troubleshooting I get a black screen, or that meant that if I try that I get a basic VGA text mod or maybe a plain old VGA 640x480 unaccelerated buffer and no extra mode it's available?
On the other side, if I use a Radeon GPU, like the 6700XT the integrated GPU could be linked to the GPU card and used to extend the screen? Basically use one HDMI connector from the external GPU and the HDMI connector of the mainboard to connect another monitor.
Maybe they're stupid questions, but it puzzles me if both of these hypotheses are false what is the use of an integrated GPU for processors meant for gaming PC that are going to use an external graphics card.
