Some users experience slowness with the new cPanel x3 (sg) theme. This is because it has many advanced features for enhanced user experience.

While there can't be done much on the server's side to speed up cPanel, there is an easy workaround:

Simply change your cPanel's style to Blue Lagoon. This can be done by logging in cPanel, going to Preferences, Change style.

This style is very fast and optimized for best performance.