First off, sorry if this isn't the right place for this but I figured if there's anyone that could help, it would be someone that either develops or uses DF. Just to get it out of the way: the issue more than likely isn't directly related to DF specifically; it's related to whatever happens "behind the scenes" (in Windows 11) when you activate more than one monitor at a time. Which is basically the main function of DF so hoping someone here might know. Anyways, some build info:

Processor 12th Gen Intel(R) Core(TM) i7-12700K (3.60 GHz)

Installed RAM 32.0 GB (31.7 GB usable)

Edition Windows 11 Pro

Version 25H2

OS build 26200.7628

Experience Windows Feature Experience Pack 1000.26100.275.0

DF version: probably not relevant but I've reproduced the issue both on the most recent beta and the current official release (11.1.1)

Basically about a week ago I noticed every single one of my games, be it on Steam, GOG, or standalone, was (mis)behaving in a similar manner right after launching said game: for about a minute or so, through the initial main menus and loading screens and actual gameplay, I'm getting one long FPS drop (like down to 5 FPS) even though my GPU/CPU aren't even at 20% utilization every single time (even for something like Rocket League, which could be run on a toaster at this point) for about the same amount of time until suddenly it's like my GPU remembers it has a job to do and I see my GPU utilization go back to what it should be, and with it, the FPS goes back to normal like nothing happened.

The above happens without fail unless I've very recently started my PC or until I eventually, even for just a second, switch to using multiple monitors at once. Not even in-game, mind you, (I always boot up on my main monitor in Fullscreen with all other monitors disabled), just at any point whatsoever since the computer's booted up.

Once this action has been triggered, SOMETHING gets tripped (here's where I hope someone has more insight/expertise) and every single game I own behaves in the manner above until I restart my PC.The issue is also resolved by the impractical process of physically unplugging every single display from my GPU until there's just 1 display connected to the PC. I can reproduce the minute-long FPS drop effect in any game indefinitely from the moment I have more than one monitor "active".

I've tried only switching from Monitor A to Monitor B one at a time, that's no issue. As soon as I allow both A and B to be active at the same time, even immediately after reboot, and even for just a second, my games are effectively "tainted" with this issue until I restart my PC.

I've tried checking running processes when it happens and don't see anything out of the ordinary or even any sort of significant usage. My main question for anyone here is: is there some sort of process or flag or something in Windows related to multimonitor usage? Specifically the "act" of having more than one active at a time. One that also (apparently) "undoes" itself when there's only a single display connected. I've tried doing a clean install of my GPU driver and everything is still behaving in the exact same manner. Could someone here maybe point me in the right direction? Gee