However recently I've noticed a problem. When connecting my MAME PC to my Home Theater projector via the HDMI port on my video card, Windows 10 would always default to the Projector as the default display when resuming from sleep, or if the Projector was on during boot.
What I wanted was for the VGA display to be the default ALWAYS (Display 1 in Windows) and for the Projector to only be enabled when I chose to do so. A non active HDMI switch worked (physically severing the connection to the projector when not in use) but this was not ideal.
After some research I found that video card bios have a locked in display order priority. I was using a DVI to VGA adpater to connect my monitor, so I thought perhaps a Display Port to VGA adapter would change the display order priority without having to change my monitor type.
A few days later, this cable arrived, and I immediately saw all my issues go away. Windows now allows me to assign my VGA display as Display 1 (I don't think it even knows it's an old CRT anymore, it thinks of it as an eqivilent display now to the Projector). The CRT is now the default in all boot scenarios and still is the primary after sleep resumes. I know this is an edge case that most people won't have to deal with, but I didn't see any information like this in my google searches so hopefully this helps someone else.
