Is oh-my-zsh slow?

I've just started using Oh My ZSH and found it to be really slow... but only when in a git repository directory using a theme that display git information (robbyrussell for example). The fix is to disable the Git feature for this theme by simply entering this in the CLI while in your Git repository:

git config --add oh-my-zsh.hide-status 1

Instant speed thanks to this Stack Overflow question and answer.