Firefox build 40.0 can no longer play any youtube.com videos without ludicrously high cpu levels on my 64 bit Windows 10 Pro system. On non HD video's, the cpu level Fir… (read more)
Firefox build 40.0 can no longer play any youtube.com videos without ludicrously high cpu levels on my 64 bit Windows 10 Pro system. On non HD video's, the cpu level Firefox is using is a constant 45-50%. On changing to 1080p HD, Firefox 40.0 is now hogging a staggering 75-85% of cpu. This has started since upgrading to Firefox 39.
Opera 31.0, Edge and Internet Explorer 11.0.10240.16384 all use less than 20% cpu when running HTML5 or Flash in 1080p HD mode on the youtube.com website.
Why is Firefox running at 75-85% cpu on my system? Video's on youtube.com are choppy and stutter and Firefox 40.0 is having a devastating effect on the smooth running of my entire system, ramping the overall cpu use right up to 100%. It manages to slow my entire operating system down. I have never had this problem with Firefox before, not even in the many Insider Preview versions of WIndows 10 Pro.
Does anyone know what is causing this unacceptable amout of cpu use by Firefox 40.0 and how to fix it? I have already uninstalled Firefox completely and re-installed it. This has had no effect whatsoever on the extreme cpu use.