He's not the only one. It's a recurring comment here on hacker news and a proble...

allenz · on Nov 1, 2018

Same here, I run the latest Firefox on both Windows and Linux. Gmail always takes at least 5 seconds to load.

cpeterso · on Nov 1, 2018

If you experience a reproducible Firefox performance problem, please consider using the Firefox profiler add-on [1] to record a profile and file a bug with "[qf]" to the whiteboard field. These "[qf]" Firefox performance bugs get reviewed by engineers twice a week. Having a profile makes the bugs much easier to diagnose.

[1] https://perf-html.io/docs/#/

rtpg · on Nov 1, 2018

I think that Chrome also suffers on this front? But it's better at doing pre-fetching than Firefox is

This could really just be that part. I have a hard time imagining explicit sabotage of FF on the gmail frontend. The likeliest explanation is that perf testing and the like only happens in Chrome

asdfasgasdgasdg · on Nov 1, 2018

The classic question to ask at this point is whether this affects you with a fresh install, or only once you have added all your extensions?