[Tracking Requested - why for this release]: A friend of mine reported that his Firefox 57 on Mac OSX consumes about 80% CPU on one core when opening the following page: https://www.amazon.de/gp/angebote/ref=nav_cs_gb I reproduced the same thing on Firefox Nightly on Linux. We tested that both Chrome and Safari consume significantly less CPU on that page so I thought it might be worthwhile to investigate this further.

Tried to reproduce this on a MBP 2015. I managed to capture a profile when Firefox was taking up 100% of my CPU in Nightly -- not sure it shows anything interesting. https://perfht.ml/2zqyhSk In general, Firefox takes up about 2-3% more CPU than Chrome after the page is loaded. I wasn't able to find a regression window, as the increase in CPU use seems to happen inconsistently. Hope the profile helps.

Possibly related? Not sure: https://www.reddit.com/r/firefox/comments/7ait0j/fixworkaround_for_lag_and_high_cpuram_usage_on/

Hey Christian, could you please try to reproduce again and if you can, capture a profile for us?

possible dupe of bug 1415387.

I tried reproducing this on Fx59 and was unsuccessful. I suspect that the site changed though. I will try to confirm this with the original reporter. Nevertheless, the URL in comment 0 still seems a little slowish on Nightly. Maybe we should investigate if there is optimization potential.

This feels incomplete. If someone can repro or provide more details, feel free to reopen.