That’s an issue I can’t give you a quick fix for. The solution is to unfortunately join servers with fewer vehicles. If you are taking it in turns drag racing, you could always request that participants not currently racing, despawn their vehicle until it’s their time on the strip. If you have lots of background applications running, CPU intensive ones specifically, you could close those and you should see a small fps improvement, assuming you are in fact CPU bound.
Cheers,
Dave