In past few weeks I’m not sure anymore about this, as I have tested running zsh on various terminal emulators (iTerm, Hyper, Kitty, Alacritty) and the result is shocking me. It turns out that iTerm is now the slowest of the bunch 😳. I don’t know exactly when Hyper is faster. The test I used is echoing some big text files and see if the scrolling is laggy or not. Now if you don’t rely on iTerm’s feature (eg. Python scripting) so much I recommend moving to other terminal emulators.