Got my Asus ROG Strix 3090 OC today.
From the Asus ROG strix 2080ti OC I did get a 58% increase in average fps in DCS /VR with the current settings I used with the 2080ti.
Lowest frame rate increased 76.5% !
This during the dcs VR benchmark posted on digitalcombatsimulators site and using my Reverb pro. Havent configured the newly arrived 8KX but things look good for this 
This is a higher increase then I expected!