no i wasnt mining when it shuts off - idle or not it still shut off. the risers are powerby 6 pin cable to PSU.

anway i did a fresh OS install and knock on wood, it seems to be working now - i have had the risered gpu detected and powered for over an hour now.

what i did different this time : disabled win10 updates after install and did not install any mobo software.also i let windows install all device drivers. so my guess is either win10 updates or the mobo AMD all-in-1 drivers caused the issue.

i did install the latest nvidia 436.30 driver. at first it didnt appear like the risered gpu was being detected, after reboot and reinstall again it finally detected. i guess windows was doing something in the background and finally detected it.