[fastball]

Ah, thanks for that, it seems you are spot on.

https://blog.chromium.org/2017/04/real-world-javascript-perf...

I actually just ran their "real-world" test (http://browserbench.org/Speedometer/), and the results were:

  Chrome 62: 39.6 ± 3.4 rpm
  Firefox 59: 27.0 ± 5.6 rpm

So there may definitely be something to this theory. Would be good to have a larger sample size though.