Disabling npm's progress bar yields a 2x npm install speed improvement
Doing GUI calls is a notorious way to slow down apps. I sped up an app (major software from major large corporation) by a factor of 10x a few years back by removing GUI updates. What you have to do is create a thread that refreshes the GUI periodically and not let your main worker thread ever work on the GUI. This particular app was an Eclipse Plugin (a source control app) and the Eclipse SWT to update the console log window was being called after every file operation (of which there were 10s of thousands). All I did was move the GUI refreshing into it's own thread, and call it only every 250millis or so. I was hailed a hero, and deservedly so, for speeding up our app by 10X and was one of my most satisfying accomplishments in my software career.