Yeah, well they know what the problem is but it fails to get a high enough priority to get solved: https://bugzilla.mozilla.org/show_bug.cgi?id=1407536

It is highly unlikely that this single issue is responsible for everything reported in this thread.

I find this confusing: there is tons of discussion in the thread, and yet:

> UNCONFIRMED

> Votes: 0 votes

Yeah plus I find it strange that their telemetry isn’t picking this up.

Hi, I'm one of the commenters on that bug.

The discussion is all specific to that page. The biggest issue is that the animations are being driven from Javascript instead of CSS, so there's little we can do to optimize it.

The rest of the discussion is possible heuristics we can implement to optimize how we layerize the page. It would potentially help on this page, but might make things slower elsewhere.

The problem is not with that page. A simple CSS animation without JS triggers the same issues.

Sorry I don't check hackernews for replies frequently.

That bug refers to high cpu load on that page. On that page it is due to the animation being driven from javascript.

If a simple CSS animation causes high cpu usage please file a separate bug with an attached test case.

If it is a JS vs CSS issue, why does it only slow things down on macOS?

The site in question on that bug is CPU heavy on all platforms

They do use a lot of Macbooks but Windows users get priority care since they're the meat of their market.