Forza Horizon 4 framedrops and stuttering

Hi there since the 4th october I do have massive framedrops ingame and my RAM is very at its limit (8GB). Also if I try to put the settings down the game still have framedrops. Since that there was a update in Forza wich meant to be the solution for my problem but it s stil there. I have also a kind of thinking that I can blame the autumn update from windows for that, thats said to be broken. The interisting thing is before that update erverything went well at 60 FPS. Do someone of you also have those problems?

Intel Xeon E3-1231 v3 3,4 Ghz
Nvidia GTX 970 Vram 4GB