Yes, for my girlfriend, during some last few months Firefox is much slower than before: she uses it mostly for Facebook and Youtube, she doesn't have any extensions installed by herself (not counting the stuff that is in Firefox because Firefox marketing initiatives, like Pocket) and no adbockers, but Firefox uses so much CPU that it gets completely unusable.

And she is not any extreme Facebook user: she has less than 500 "friends." And she doesn't have big "subscriptions" list in Youtube.

So it's completely opposite of the propaganda: the average user, using the most common sites, is hit to the that much CPU more use that the most common sites are unusable.

So what's going on here? It's just the propaganda machine claiming the opposite of what is actually happening at the moment. They maybe have good goals but at the moment it's worse than, for example, a year ago.

Maybe it's because she doesn't have a newly bought computer, which are the ones used by those who test? And I guess those who test don't use Facebook and Youtube?

I also use Firefox but spend zero time in Facebook and minimal time on Youtube and block Javascript wherever I can, so I don't see the same. But I saw the CPU on her computer staying completely blocked by something Firefox is doing. The only thing I was able to figure out: around 40 percent is spent in kernel according to the task manager. Both cores are used more than 90 percent, and the Firefox is not responsive. She doesn't do anything more than scrolling down her Facebook to see that effect. It's not always that bad, obviously depends on the content on the Facebook, but it's bad often enough for her to see the slowness regularly, and when it really gets stuck to complain to me.

What I personally observe is the pages embedding more linked Youtube videos got to be very slow to even display them. Those are the pages I stumble on occasionally, so I didn't investigate. The second effect I've observed is writing a longer post for HN on Firefox getting much slower (less responsive) the longer the post is. Like writing these words now.

So, dear Firefox people, your product is really SLOWER for me too in the last versions, and not faster. And it is extremely slower for a "normal" user using the "normal" Facebook and Youtube.

(Additionally, I use a number of extensions, and only one will remain available soon when they turn off the support for what they mark as "legacy" extensions. That is really strange decision, deciding to remove the major difference between them and Chrome, becoming just as limited as Chrome is for extensions and wasting the work of most of the extension developers.)