Compile your own emacs for your particular processor using all the available optimizations and you might be running much faster than your OS's emacs. You can also opt for other speedups and enhancements which you won't find in the normal generic emacs.

It's even possible that if you're on an old netbook, your emacs is using optimizations which don't exist on your machine causing all kinds of extra processing. Who knows. I also don't use GTK at all, this is a massive speed-up.