A quick test on just one HD video using FF43 64-bit and my CPU usage appears to be much lower but I will need to do further testing later to be sure if Mozilla have sorted their HTML5 Player. Anyone else who reported high CPU usage earlier want to check again on their machines? Edit: Possibly related to this from the Release Notes? Improved API support for m4v video playback
I remembered reading "high cpu usage" on a Ghacks website (). I don't think it is html5 related, but according to the creator, it lifts cpu temp... might want to check to see if this setting exists, assuming you use firefox... Code: // FF40 - turn on APZ ( Async Pan/Zoom ) - all this seems to do is lift my CPU temp // user_pref("layers.async-pan-zoom.enabled", true); Maybe this also applies to v42?
Without making any changes in about:config, FF43 is using much less CPU usage than FF42 while watching HD videos on youtube. I'd have to say Mozilla have got on top of this issue, for me so far anyway.
I'd still like to hear from others but so far I want to say FF43 has fixed the high CPU problem for me.
HTML5 is shown by the openh264 codec from cisco. i dont know how much mozilla is concerned but i would say its development is cisco. at least on older machines it can stutter depending on resolution. as mentioned antivirus with active stream scanning may slow down. if v43 solved your issue this is an improvement as expected, btw 43.01 is ready and 43.0.2 will come. btw i wont count on other forkes - either slow by development or compilation or same engine/same plugin - all would have same issues, even on x64.