Hi briandsk, Thank you for your question about Firefox for Android Performance. Thank you for elaborating. Currently the Nightly version of Firefox update more often then the stable releases of Firefox. It is on a rapid release cycle. Do you happen to have the version number of nightly when this started happening? This can help narrow down what edits to look through :-) Also the Telementary data sent on the browsers can help improve the performance. There are also automated tests done to check performance of different platforms. If you are interested in providing a website example this could help create a bug. With the websites, there are have these tools to test the performance of the profile as well: This will test the javascript engine on desktop: [https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Reporting_a_Performance_Problem] and for android local host builds these test can be reproduced here: [https://developer.mozilla.org/en-US/docs/Mozilla/Performance/Profiling_with_the_Built-in_Profiler#Profiling_Firefox_mobile] There is also DTrace that can help optimize development on javascript pages [https://wiki.mozilla.org/Performance/Optimizing_JavaScript_with_DTrace#Tips] We look forward to your reply