Problem is not 1070 or 1080TI or not, problem is that dcs is not optimized good for VR, simply uses GPU badly. Can say names here but there is couple of sims that run great in VR, look least good as dcs or better :)
So just have to wait that ed fixes this more.
-edit- And before someone says something about " dcs makes calculations or is complex and so diffrent because reason xxx, just take Mig-29, empty clear map. Sit in, turn it off = now you have quite low cpu load. And still VR fps sucks , its just not done right yet.