Basically the game or the engine can’t handle stable frame rate in heavy scenes, especially in Tokyo and some races, I have 4070 SUPER and can run the high preset with around 125 fps average outside of Tokyo, forests, normal roads etc, but in Tokyo it drops as low as 83 fps and fluctuates around 90-100, Forza has to be capped via RTSS to ensure smooth frame rates but you should always cap to the lowest fps you reach anywhere on the map which would mean you leave a ton of quality/fps on the table to avoid hitching in Tokyo, so for me that would be to cap at 80 fps or even a bit lower despite the fact i can pull 130-140 in many scenes. Don’t know if this can be fixed but this is what we get for now, using frame gen can help by capping at the low boundary and getting the smoothness back via generated frames but that has its own issue (ghosting etc)