I don't get any "ghosting" in warthunder, elite dangerous or any other game I play, so don't think it is my headset. I am quite sure it is ASW artifact.
Edit: Finally found a way to disable ASW in DCS(using profile in oculus tray tool), and the aircraft flying by double-images are gone! However overall game judder now introduced. One step forward and one step back. Guess DCS is much more demanding than warthunder or elite dangerous. I already have a GTX1080 ,guess it is time to upgrade my cpu/mobo.