If you have the time, please file a bug at https://bugzilla.mozilla.org/ it's pretty painless. We definitely care about Firefox on Mac. Thanks.

Would be great if you could start to care about Firefox on Linux, too. (It's the only platform where hardware acceleration is disabled for example https://bugzilla.mozilla.org/show_bug.cgi?id=1280523)

Yeah, it's really weird that you STILL have to force enable it through about:config. Come on Mozilla… Mesa 17 has arguably the best OpenGL implementation ever.

I can confirm that the 57 beta has acceleration enabled by default on Linux.

Are you sure? You need to check about:support, as the checkbox in the settings does nothing on Linux. It still says

HW_COMPOSITING blocked by default: Acceleration blocked by platform

for me with Nightly (57) on Linux.

I also have very poor performance with my 2015 rMBP and external Dell 4K display, but it's almost as bad without the display.

Although performance is greatly improved (and, seriously, the developers should be proud of the progress), there's still a lot of work to be done. There's significant lag in even non-network UI (e.g., highlighting the row under the cursor in about:config lags behind the mouse cursor by almost a second).

As much respect as I have for the developers for this progress, I still can't really use software that makes me feel like I'm intoxicated.

try a profile reset https://support.mozilla.org/en-US/kb/refresh-firefox-reset-a...

I tried. Didn't help.

If the issue is as bad as it looks like in that screenshot, the performance profiler should be able to spot what's happening easily. Take a look at https://perf-html.io/

I wonder if MacOS just isn't that much of a priority for Firefox? Popular but heavy sites like Facebook perform quite poorly relative to Chrome on my (admittedly quite old) early 2013 MBP, but the difference seems to vanish under Linux or Windows.

I'd love to switch to Firefox, I'm not that keen to be running a browser made by a gargantuan advertising agency.

> I wonder if MacOS just isn't that much of a priority for Firefox?

Hardly, most Mozilla people I've seen use a Mac, if anything, it's Linux that is a bit less of a priority it seems.

MacOS seems not to be a priority for Apple, sadly.

I had the same problem from time to time when a Google search result page was open. Closing it made everything normal again. It'd be interesting to know if that was only me or if others have the same problem.

I'm convinced it's because of CSS animations / transitions. Firefox seems to be doing just fine loading static sites like HN. Stripe.com however seems to be Firefox worst nightmare.

I would love to hear from others who have this problem too. In fact I have a 15" MBP and a 4k Dell monitor at work so when I get back next week I will test it too.