The current version of the program is 2019.1.2. A new version is releasing in a few days. Always make sure to be up to date before reporting problems, to eliminate potential issues with using an outdated version.
There is a “rotate speed” setting in the preferences (Preferences > Interface> Navigation). This is maxed out by default, so you would have had to specifically change this. Remember to store config after making changes in the preferences to save them for the next startup.
It’s also possible there’s simply a different rotational pivot on each version of the model. A different rotational center may appear to make each model move at different speeds, depending on how off screen the pivot is. Make contact with the model with your brush, and it will will then rotate around the last point of contact.