I just swapped my R9 290X TriX with an Vega 64 Liquid Edition.
The first one I got was a dead-on-arrival (went on/off/on/off/...). The second one works, but now windows is showing a second, non existent monitor every other boot.
When opening the device manager, I can see my LG monitor which is hooked up to my Vega 64. AND then there is a non-PNP monitor that is supposed to be hooked up to a microsoft video card. My onboard GPU is disabled (was enabled at first, then disabled it to check if this is the source...). When swapping back to my 290X the issue is gone (with either onboard GPU on or off).
Except for this the card is working and performing just fine.
Can anyone help?