take the full amount of pixels, reduce the resolution by half, upscale the picture by 2 adding sharpening before resizing, repeat picture similar to the vive asw.
the result is 45 fps doubled to 90 fps, and the 45 fps is half the resolution.
to repeat this process, reduce the original pixel resolution by 4 times, then do 2 resizing steps. the 1/4 pixels is sharpened then resized by 2x, then sharpened and resized 2x again. this way your lowering the amount of pixels to process by 4 times. I showed in my how to upscale dvd the process, and in my tests this is how to resize correctly.
don't do any msaa. lower the super sampling or use no super sampling.https://uploadvr.com/htc-vive-motion-smoothing-specification/
"Motion Smoothing works very much like ASW. When you’re not meeting (or near) 90FPS in VR, Motion Smoothing will kick in automatically. Motion Smoothing will force the running game/app to render at 45FPS, then generate a synthetic frame in between each real frame, extrapolating from image and the headset tracking data for a total of 90FPS. Half the frames will be “real” and half “synthetic”. Whenever your graphics card has enough free resources to achieve 90FPS normally, Motion Smoothing will automatically disengage and you will return to true 90FPS."