EDIT: In case anyone happens across this post, my issues so far seem to have been resolved via re-seating my GPU. No idea why it started happening in the first place still, but it did fix it.

(Duplicating my post from r/buildapchelp)

Hey folks, I've been encountering a problem with my rig performing way under how it normally does unless I boot it in a particular way. I noticed this problem after getting my AW3821DW (referred to as the 38" from here on) monitor. I don't believe it's the cause, but it did surface soon after getting it. I also have an Acer Predator XB271HU (referred to as the 27" from here on) that used to be my main monitor which is now on the side.

So right now, the "correct" steps to ensure full performance of my rig during start up:

1. Unplug the 38" from the GPU DisplayPort
2. Ensure the 27" is plugged in to a specific DP port (other ports may work too, but that one almost guarantees a POST)
3. Wait for PC to POST and get to Windows log in screen
4. Plug the 38" back in to one of the remaining DP ports
5. Either one of two things happen
   • If I'm lucky, the signal swaps successfully and I (probably) have my PC functioning as usual
   • If I'm not lucky, then the screens will go black for a moment, then return to POST. Start from step 1. It might also signal swap successfully but game performance is terrible. Shut down and start from step 1.

When this happens, I get very degraded performance. If a game normally runs at 120fps, I see it run at anywhere from 25% to 75% of the 120 that I should be seeing.

Here's a list of things I've tried in no particular order:

• Disable the Fast Startup option from power settings (referenced here with similar symptoms)
• Set power settings to High Performance
• Making sure NVidia drivers are up to date (as of 11/2/2022)
• Download all current available Windows 10 updates including a Dell monitor driver in the optional section
• Boot with only the 38" connected and check performance (same degraded performance)

Any suggestions? I'm kind of pulling my hair out over why this started happening.

Build specs (ignore prices, mostly bogus): PCPartPicker Part List