Hey Jonas, So regarding to your problem there are several ways to speed up your browser. 1) Type this on search bar and accept

         about:config 

Then there is a search bar and type browser.tabs.remote.autostart. Make it to false by double clicking on it.

2) Use hardware acceleration. For that first you have to go option>general>performance. There will be selected "use recommended performance by default. Deselect it and select "use hardware acceleration".

3)Run maintenance scrip on your mac.

Hi, thanks for you answer. Could you explain the rationale of these suggestions? Google says that since Firefox 68 the autostart settings has no effect? What maintenance script are you talking about?

Hi, You can run maintenance script by manually or by a third party application.

First open terminal prompt and type following exactly as written.

"sudo periodic daily weekly monthly"

or you can try a third party application that can run maintenance script.

After the process restart firefox browser

But what does this have to do with Firefox when it's a system function? If my system is slow due to the lack of `periodic` runs, then other browsers must be slow too, right?

Sometimes it cause the problem, but if you try a third party application it diagnoses all the problems and execute the process automatically..Did you try the other methods that I mentioned earlier??

Hi,

One of the reasons why your Mozilla Firefox is slowing down on mac is the OS version you are using. Also, if you haven't deleted the caches and history in your Firefox browser for a long time, the firebox can slow down. So keep a history of your recent use and need. Delete everything you don't need.

Click the Library in the menu bar and click on History. Then select Show all history at the bottom. From that, just delete the rest of the history you want. This will increase your Firefox speed slightly.

Menu bar>>Library>>History>>Show all history

I hope my suggestion helps you a bit.

ishanchanuka4 your suggestions 1) and 3) do not make any sense, 2) I tried, thanks for the hint, but doesn't make a difference.

Hansi Gayathma, why would my OS version make a difference here? Chrome and Safari on same OS are much faster. I just tried with a fresh profile without any plugins, with suggestion 2), on Firefox 75 and it's still much slower than Chrome.

Even this very page (support.mozilla.org) works much better in Safari...

Hi, Use hardware acceleration. Hardware acceleration is when a browser uses a computer's GPU to load pages more quickly, which is something you can do with Firefox Quantum. ... Delete Internet plugins. ... Switch off data collection. ... Switch off Accessibility Services. ... Run Mac Maintenance Scripts.

Thank you.

Thanks chamodie1996 for the suggestions. I did change all these settings and restarted Firefox. It's still much slower than Chrome and Safari.

The virus guard we use checks the sites we browse through. If our browser is not compatible with the virus guard, the browser may slow down. So everything needs to be updated. Even then, the PC is easy.

I don't have any kind of anti virus software installed, this is a pretty vanilla macOS installation