How American Truck Simulator runs on the Radeon RX 580
Our estimate puts the Radeon RX 580 at about 55 fps on High at 1080p in American Truck Simulator, which means it runs acceptably. On Low the same card manages about 104 fps, and on Ultra about 39.
The graphics card is the limit here, so lowering the resolution or the quality preset is what raises your frame rate.
For a steady 60 fps, our estimate says: 1080p: Medium (about 76 fps); 1440p: Low (about 75 fps); 4K: under 60 fps at every preset, best is 41 fps on Low.