I know preparations are underway to add a new part of a preferences tab for performance, and so enable us to make changes that get the best out of Firefox.

For a long while Firefox has been able to run plugins like FlashPlayer in a separate plugin container the idea being to help by separating the process whilst your Flash video plays.

Firefox is now multi process. In many cases this should improve Firefox's performance. Running two (or more) processes should not double (etc) your ram and CPU use, and many users will have spare ram & CPU capacity.

If you have problems then at present it is not straightforward you need to use about:config to reset a couple of preferences:

• See this news website https://www.ghacks.net/2016/07/22/multi-process-firefox/
• and this mozillazine article http://kb.mozillazine.org/about:config

1. Use about:config by keying about:config in to the address bar, hitting the Enter Key and accepting any warning
2. Then use the filter to search for e.au and look specifically for anything starting browser.tabs.remote.autostart there may be a number following that:
   • browser.tabs.remote.autostart = false
   • browser.tabs.remote.autostart.2 = false
3. Use the right click option to toggle the preference to false.

Ok i read both articles. The first one does say there's an increase in Ram usage by 20%, but that's nowhere near double.

I'll check addon compatibility as soon as I'm able. Thank you for the info.

Okay... did some testing. Disabling addons, switching the new feature on/off.

Addons are 100% compatible according to others. Avast internet security and Ublock. Disabling had 0 effect on performance in any mode. As for the feature itself. It uses anywhere between 500mb and 1.1GB of RAM and 40-80% CPU when watching a video or viewing anything with a lot of multimedia files (sound, video or hd pictures). 2 Processes stand out, Flash player and the secondary Firefox process.

When the feature is off...Firefox uses between 300mb and 800mb RAM and 60-90 % CPU. As expected ram is down by 20% and CPU is up by 10-20%. Even so... 1GB and 90% CPU is a little over the top for a simple youtube video on a facebook page.

On my other PC, this is not at all noticeable since i have an i7 and 4GB. But on my laptop... games that are 3 years ahead of this laptop don't use as much resources.

Hi niktr, Sorry for the delay in replying.

I am not too sure how unusual your results are. I know Facebook is a very complicated site and also I have seen reports of memory issues using facebook, but they seem to have been put down to being as expected for such a site and the way it is used.

Flash Player is something that has often caused problems one way or another, and Plugins are being phased out, FlashPlayer being just about the last survivor. What happens if you test and use the YouTube site and its HTML5 videos, how does the usage compare then with and without multiprocess Firefox.

Note some of the pre release versions of Firefox are testing out methods of making it easier to control performance features and settings so that Firefox users may be more likely to get the best out of their device. Clearly settings that benefit a modern Higher Spec. machine may be unsuitable for an older low spec device.

@niktr :
Maybe you'd like to (temporarily) create a new profile, to see if that has any effect. See :
https://www.reddit.com/r/techsupport/comments/5o4qfd/firefox_is_using_a_lot_of_cpu_is_that_normal/

Videos on YouTube use slightly less resources. I'd estimate about 10-20% less. Though it doesn't completely freeze the browser it does have lag spikes over time. Let's say my laptop is too old for youtube... Wouldn't embedded videos use html5 too?

Weird. I guess I will try that, thanks.