Performance mode changes the system parameters of your Mac. These changes take better advantage of your hardware for demanding server applications.
A Mac with macOS Server that needs to run high-performance services can turn on performance mode to dedicate additional system resources for server applications. Note, however, that performance mode can be enabled even without macOS Server being installed to achieve similar benifits for other high-performance services.
sudo nvram boot-args="serverperfmode=1 $(nvram boot-args 2>/dev/null | cut -f 2-)"
sudo reboot
Reference: https://support.apple.com/en-us/HT202528.
