Why do you ask? Are you having problems with your current setup?
To answer the question: incremental CPU upgrades like the one you mention won't necessarily result in significant improvements. While games obviously need a CPU, the bottleneck is more likely an underpowered GPU. As a 2600X is almost twice as capable as Frontier's recommended specification, a 3600X will make negligable difference. A GPU upgrade, however, is much more likely to help, especially if you're playing Horizons.