Here's the low down on my setup:
R5 1600 (not OC'd)
16GB Corsair RAM
Gigabyte AX370 Gaming
XFX GTS Black Edition RX 580 8GB
EVGA GQ 750W
Monitor 1 - AOC G2460PF (1080p 144hz, connected through DP)
Monitor 2 - Dell 1704FPVS (cheapo 5:4 screen, using a DVI-I adapter to VGA to connect to monitor)
(also an Oculus Rift, but that doesn't seem to be a factor in this issue)
I'm experiencing a newly onset issue (So it's not a compatibility issue with the adapter, my 580, or the montior) with my 580 where the second monitor when connected and booted up, does not receive a signal from my 580. As far as I can tell, it's not a driver issue, as I've used DDU and installed different/older WHQL drivers with seemingly no effect. It also doesn't seem to be a windows *version* issue, as it didn't present after a specific update (as far as I know) and updating from 183XX to 1903 hasn't changed the issue. It might be related to the issue others are having which was listed as a known issue in 18.8.2 where:
- Cursor or system lag may be observed on some system configurations when two or more displays are connected and one display is powered off.
Although it seems like the issues people are having are multifaceted as this issue also occurs for others when the PC falls asleep. This issue isn't the same as mine however, because my main monitor stays powered on throughout the issue, and I've made changes to the power settings in windows to prevent the PC from falling asleep and I still encounter the issue.
An interesting thing is that I can get the second monitor to connect/be detected if I:
1. disconnect the DVI adapter from the PC
2. reconnect the only the adapter to the PC, this doesn't work if the VGA cable is plugged in on the other side of the adapter
3. plug in the VGA cable to the adapter.
This will connect the second monitor, but renders the PC unusable due to system lag, which I believe is the second monitor interacting/disrupting with WDDM/DWM. During one of my stints trying to fix the issue, when the monitor would disconnect/reconnect I heard the standard windows USB disconnect/reconnect sounds, similar to one of the other issues I mentioned earlier. Here's a video I've taken of the issue: 580 Issue - YouTube
While I doubt it, it could be related to the issue that many 580 GTS owners encounter regarding blackscreens and high temps/VRAM usage, and while I do encounter this issue, I don't think it's related.
Any help regarding this issue would be highly appreciated, I'm really missing my second monitor 
