I to have bad performance with Dcs and VD. I am only getting 33fps in cockpit. If I look up at the sky I get 66fps. With usb 2 I got slight better performance but the image is not as good as with VD.
i have activated 90hz via sidequest but it doesn't help.
Other games runs fine on VD.
I have a ryzen 3700x 1080ti 32gb ram and all installed on an SSD.