Instead of accepting that Firefox may indeed have performance problem, you immediately discount this possibility, instead blaming it on mr_november's computer.
It's irrelevant that it isn't happening on your laptop that's over 2 years newer than his is. It's irrelevant that it isn't happening on your Ubuntu system. None of that matters.
I don't doubt for a second that he is in fact running into performance problems with Firefox. He isn't alone. Many people report Firefox having worse performance than Chrome does on the same system. I've experienced this, too.
Yet instead of addressing and fixing these very real performance problems that have been brought up time and time again by many users, the Firefox community and developers seem content to deny that they exist, or refuse to consider that it may be a problem with Firefox (like you've done), or point to useless and totally unrealistic benchmarks to suggest it isn't a problem.
But worst of all is how mr_november's comment has been voted down. It's one thing to deny that the problem exists, but it's much worse to try to actively censor those who have merely pointed out a very legitimate and troubling issue.
Firefox has been losing market share for some time now, and this trend will only continue as long as Firefox's performance problems go unaddressed, and the Firefox community mistreats anyone who dares mention that such problems still exist.
