I have never profiled where the bottleneck is, but if I had relativenumber and cursorline set, I could see it literally redraw the screen (on both Intel and nVi

I have never profiled where the bottleneck is, but if I had relativenumber and cursorline set, I could see it literally redraw the screen (on both Intel and nVidia GPUs). Luckily, it's a bit better now on my MacBook Air 2012 and the latest MacVim. But it used to be so bad that I often unset these options.