[Tip] How to Disable Tab Warming Feature in Mozilla Firefox

Mozilla is continuously working to improve the performance of its popular web browser “Firefox“. When Mozilla introduced the new Firefox Quantum version, it came with lots of performance improvements and UI changes.

With the release of Firefox 61.0 version, Mozilla has added a new feature called “Tab Warming” to Firefox. If you remember, we told you about this feature when Firefox 61.0 was under development and testing. Check out UPDATE 116 in our following exclusive topic:

Mozilla Firefox Nightly Build Updates

Tab warming feature has been implemented to make the tab switching faster in Firefox. It works by preloading a webpage content in the background as soon as you hover the mouse cursor over its tab. So basically Firefox starts loading the page in background when you hover the cursor over that tab. So when you actually click on that tab, it opens faster.

Actually when you switch to a tab in Firefox, a message is sent to the content process to ask it to paint its layers and then the browser waits for the compositor to tell that it had received those layers before finally doing the tab switch. Tab warming pre-emptively renders the layers for a tab and pre-emptively uploads them to the compositor, when you’re likely to switch to that tab.

Tab warming looks a nice feature addition but for some people it might be an unnecessary feature addition which might use their CPU resources for no benefit.

What if the browser starts preloading the tab content and you do not switch to that tab? In that case the browser will throw away the uploaded layers but it has already wasted your system resources in preloading the tab content.

Some users might also face tab switching problems due to tab warming feature enabled. I have also personally faced an issue when I switch to a tab and the processing circle in the middle of the tab keeps spinning continuously for a few seconds and then loads the tab content. I’m sure it happens due to tab warming feature.

If you are also facing tab switching related problems in Mozilla Firefox and don’t find the new tab warming feature useful, you can disable the feature to fix the issues and stop Firefox from wasting your system resources.

You can disable tab warming feature using the hidden secret advanced configuration page i.e. about:config page. Check out following simple steps to deactivate tab warming feature in Firefox:

1. Open Mozilla Firefox and type about:config in the addressbar and press Enter. It’ll show you a warning message, click on “I accept the risk!” button.

2. Now type warmup in Search filter box and it’ll show following preference in the window:

3. This preference is set to true by default i.e. enabled. To disable the feature, double-click on browser.tabs.remote.warmup.enabled preference and change its value to false. Alternatively, you can right-click on the preference and select Toggle option.

That’s it. It’ll disable tab warming feature completely in Mozilla Firefox.

PS: You’ll also see two more preferences browser.tabs.remote.warmup.maxTabs and browser.tabs.remote.warmup.unloadDelayMs on the about:config page. As the name suggests, these 2 preferences are also related to tab warming feature and you can change maximum tabs amount to be preloaded by the browser and time to unload the tab content using these preferences.