I just wanted to report/confirm the system lag issue with a multi-monitors setup.
The release notes state this:
Cursor or system lag may be observed on some system configurations when two or more displays are connected and one display is powered off
And this is exactly what happens on my system (with 1 exception) which i upgraded about 10 weeks ago. I updated the CPU-Mobo-Ram to AMD Ryzen 1700X, Asus PRIME-B350-PLUS, Corsair 16GB. I did not do a clean Windows 10 install but removed the old display drivers using a display driver removal tool and installed display driver version 18.6.1 and that's where this issue started. Later versions still have the same issue.
This lag occurs when i have the 1st display turned off, it also occurs when i turn the 5th monitor ON. That's a DVI monitor and unfortunately i can't use that now because of the system lag.
I hope this issue can be fixed and if needed i can provide more info. My graphics card is a Sapphire RX580 Nitro 8GB.