Summary of issue: Both monitors connected to GPU via DisplayPort. S2721DGF has always worked fine, however P2213 continuously cycles into Power Saving Mode, goes to sleep, and then immediately tries turning back on. This monitor is detected in Display Settings, shows up in Device Manager as Generic PnP Monitor. I've been able to disable the GPU within Device Manager, which is the only time this second monitor works (however the S2721DGF does not work when this is the case). I know that the second monitor is decently old (2012 I believe), but I would think it should still be compatible with my computer. I've swapped DisplayPort cables between the two monitors, but the behavior is the same. I'd really like to use the P2213 as a secondary monitor for OBS Studio/Twitch chat, so am trying to avoid purchasing a brand new $300+ monitor that I know will work. I believe I've tried all possible solutions, but I'm open to any ideas/feedback. Thank you!
Operating System: Windows 10 Pro
CPU: AMD Ryzen 5 3600, no overclock
GPU: XFX Speedster AMD Radeon 6600 XT (driver version 30.0.15021.11005)
Motherboard: MSI B550 Gaming X V2 with BIOS version F15d (May 2022)
RAM: 2x16GB DDR4-3200 OLOY
PSU: EVGA 600 BA
Monitor: Dell S2721DGF with included DisplayPort cable, Dell P2213 with DisplayPort cable
Hey I see you ran into a similar dilemma i had with my RX 6500XT on the same P2213 this might help. If you have a spare cable lying around reinstall your amd driver using an hdmi to vga adapter and then once the driver is installed plug the display cable in the GPU and then into the P2213 as you see you get the power saving error return to the vga mode. Now using Custom Resolution Utility, Custom Resolution Utility (CRU) 1.5.1 Download | TechSpot here is the link to the program. Now that you are in the Custom Resolution program go to the detailed resolution slot then edit the one that says 1680x1050@60hz now go and change the refresh rate to 75HZ which can be done btw and then at the top where you see timings select Automatic(PC) now click ok then exit the program. Now find the custom resolution program and run restart.exe and this will restart your gpu drivers. Now go into windows 10 or 11 display settings go to advanced display settings and change the refresh rate of the display port to 75HZ and now select display port on the monitor and it should work.
Any questions fill free to ask. I just made this account as i saw this post trying to research why my gpu didnt work on my display turns out i can make a custom resolution and fix the problem by changing the timings in custom resolutions. I hope this helps.