oculus upgrade - lower performance

hello forum fellows and fellowettes

if this is in thr wrong place please shift me to the right place :)

i was given a Oculus Rift S and i have a Rift CV1, i use the S and i know its a 80hz over the CV1 is 90hz
when playing any game such as I Expect you to die / project cars 2 / asseto corsa (modded) and fallout 4 vr on my CV1 its solid...well solid as solid can be but using the Rift S its chugging/clear laggs, the drops on the CV1 are little to barley obvious, not enough to break the immersion but the Rift S it really hammers.
i have tried reinstalling the oculus/meta software, cleared the regisrty for anything oculus/meta related and even retrimmed the drive its on. my CV1 was plugged in via a HDMI to DP and the rift S being DP it took the original port, ive also tried unplugging my second screen as a maybe its the reason, ive also turned off the stuff in experimental on oculus/meta as on the CV1 it helped so thought maybe it was a issue on this one, i have also tried a second cable which made it worse, cleaned the pins on the headset, they are gleaming so i know its not that, a friend did take it away and test the points inside the unit an said it was good and even was suprised it wasnt full of dust.

any ideas what i can do as i tried it on my partners pc and it runs flawlessly except Project cars and asseto corsa with mods but Job sim and the light weight work great, Her specs are on here under system 2, the usbs ive tried in the red and blues, didnt make a differnce, only usbs i have plugged in are a keyboard and mouse on my usb2 sockets