If lowering resolution doesn't give more fps, your processor is the limit.
Not the overall cpu load, but the single core speed.
Assetto corsa can't make use of many cpu cores. The bottleneck is the speed of the few cores it can use.
Don't be fooled though:
Taskmanager etc might show ac causing some load on all your cpu cores. But at 4 GHz, the cores do 4.000.000.000 cycles per second.
If Taskmanager has a refresh cycle of 1.0s, you're seeing that cpu cycles amount averaged!
In reality, all cores that show some cpu load where at full load for a few cpu cycles and then the next core took over.
It's more efficient to shuffle the load around.
Search for ac cpu optimization, bottleneck, performance, csp settings.
In general: everything that's only visual = graphics card load.
Everything that is actually physically calculated = cpu load.
Sadly there aren't many things to reduce cpu load:
- shadows (not really the resolution, the amount is the issue.)
- reflections (again not the resolution but the update rate. So put them to static will help)
- World details
- AI cars
- view distance of mirrors and reflections
- weather fx
- night lights
- HUD apps
- rain
- reflections fx