Hi, thank you for taking the time to read my thread.
 
OS: Windows 10 (UEFI)
Motherboard: EVGA Z490 DarkKP
GPU: EVGA 3090 ti
BIOS Configuration: Internal Graphics and CSM are disabled (UEFI).
 
When connecting more than one (1) monitor - Window's OS changes my primary display's assigned number from 1 to 2. The second display is now assigned 1 and my primary is 2.
 
My primary monitor is connected to (display)port 1. The port labelled as 1 in "port priority" (see evga.com/support/faq/FAQdetails.aspx?faqid=59560). If I connect a second display to my RTX 30 Series the monitor (primary on port 1) is immediately changed from 1 to 2 and remains 2 on reboot or until the second display is physically removed.
 
I see entries in Window's OS Boot Configuration Data such as, "displayorder" and "toolsdisplayorder" (elevated cmd/powershell, "bcdedit /enum all").

I understand three registry keys are defined here:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Configuration
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\Connectivity
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\GraphicsDrivers\ScaleFactors


1) Does Window's OS read from the GPU's BIOS to apply/determine a monitor's assigned number?
2) How can I preserve my monitor's assigned number, "1", when connecting a second display?

Who is the source of my frustration ? Is NVIDIA (potentially EVGA's BIOS?) or Microsoft responsible ! ? 
 

 
 

EVGATech_LeeM
When you have both monitors connected, which monitor does the BIOS show up on?  That's going to be the way the card is telling you monitor priority.
 
If Windows has other plans, then something is going on with the way Windows is ordering the monitor numbers.  You can try reinstalling the drivers with a clean install, or use DDU, for example to see if Windows has its own pattern going on.

BIOS shows up on my primary display ("port priority 1") with both monitors connected.
 
Has anyone been able to get around my issue?
 
I always use DDU and only keep one display connected (on "port priority 1") during a clean install of NVIDIA drivers. 

Did you try steps 2 and 3 in my previos post above?  If not, give this a try.  Plug both your monitors into any of the 3 DP ports on the GPU.  Load windows and check to see how the NV CPl shows them.  If it's opposite of the way you wanted, shut down and swap the 2 DP cables using the same 2 DP ports.  See if that works out for you.  Because you appear to have 2 matching displays, this could be all hit or miss.  I have no trouble setting the order for my 4 displays using the method I described.  Only difference being mine are all different manufacturers.