Got my new Rx5600xt two days ago, fitted in, download auto-detect to get drivers - only one screen working at time. Monitor 1: Acer 19" old lcd monitor connected to DP via VGA-DP adapter
Monitor 2: Sungoo 19" old lcd monitor connected to HDMI
If I got them both - first one working, leave second one only - its working fine. Together - only one (1st). Got new PSU as well 700W so don`t think thats a problem. Drivers maybe?
