There is no harm in troubleshooting to find out.

First, please update to the most recent version of Firefox:

• Update Firefox to the latest release

Second: Quick fixes if your Firefox slows down

Third: Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

I believe I have tried everything that was previously mentioned. I have found out that Firefox is consuming high CPU and memory usage. What can I try to lower the usages? I believe that is why the Browser is so slow.

 Attached are screen shots of a website and my performance & reliability monitor at the time I was on this particular website and after it had stabilized as much as possible.  It is showing a average CPU usage of 22.41% and that was one of the lowest readings I have seen lately.

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/d.../Reporting_a_Performance_Problem and for android local host builds these test can be reproduced here: https://developer.mozilla.org/en-US/d.../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#Ti...

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10