Is anyone else getting this same problem, it is fine whilst in single player mode, but when i get on track in mutiplayer all the sound is ok but the screen slows. Very strange!! Im at a loss to what it could be.
Try turning HDR off and maybe a few of the graphics options down a bit.
Don't know how powerfull your system is? A bit more information might get you the answer you are looking for.
i have the exact same problem, also i just see the other cars for about 10 seconds, then they all dissaper. And I constantly have thetext "syncroniseing" displayed at the bottom left...
Its not a stutter its a slow down. Only seems to happen for me if loads of people are joining and leaving server at the same time, maybe its a temp car loading issue or something??