I have periodically had firefox problems in performance on all platforms including the new Mac air I bought my wife, her old Mac Pro and various Ubuntu and Windows installations. As a general rule it is because I've kept it open for several days with lots of tabs with media in them running. I mean it's irritating but not an ongoing catastrophe that means I can't use. As I said in some other thread recently I have over the past 10 years I think had two occasions where FF performance was so bad I had to leave the platform for a some time until it was fixed.
I see a lot of people in this thread claiming problems, and I see a lot of people claiming no problems, and some like me in between. So I don't know what the statistical breakdown of performance complaints about FF in comparison to all other issues (and if those complaints are actually likely to be related), but maybe it is not as great as you think it is?
Searching Google for "FF performance issues site:reddit.com" time span : last 24H, and off course there is a thread where the highest rated comment is someone saying FF is "laggy" on OSX :https://www.reddit.com/r/mac/comments/a3gk1k/macbook_air_201...
My guess would be most people have issues but most consumers don't know better. Some have no issues, and it seems that's the ones with older "non retina" displays.
Also slow is relative. If someone hasn't had an experience with a faster browser, then "slow" just feels normal. I had that after using Firefox for ~9 months. It just felt normal, and then got a bit slow and unusable after a while. After switching back to Chrome on Mac, it was like a breath of fresh air. I forgot what a responsive UI felt like.
"Yes we are aware that a certain percentage has severe performance problems on osx, we believe this has to do with the Retina displays blah blah" - instead it seems like no one from the dev group has been following this problem when you ask them. Despite weekly threads, just like the posts here on Hackernews in every FF thread.
If the Mozilla devs aren't paying attention to and haven't remedied the problem you're experiencing, perhaps you're the edge case?
I just wrote that their support subreddit is filled with posts about performance on OSX, this thread in itself already has loads of posts with people complaining about it, and my post just is getting lots of upvotes - how is that an edge case? Also all Firefox threads on Hackernews has these posts, every single one.
As i said before i have been following this for years. You having a 2012 computer is 100% the edge case - not that there is anything wrong in that, i love keeping tech for as long as possible.
