firefoxMozilla yesterday announced the release of Firefox 54 web browser with new multi-process architecture that promises to make browsing with multiple tabs open faster and more stable, especially on computers with 8GB of memory or less.

With the latest release, Firefox uses up to four processes to run web page content across all open tabs. This means that a heavy, complex web page in one tab has a much lower impact on the responsiveness and speed of other tabs, according to Mozilla:

The old Firefox used a single process to run all the tabs in a browser. Modern browsers split the load into several independent processes. We named our project to split Firefox into multiple processes 'Electrolysis' (or E10s) after the chemical process that divides water into its core elements. E10s is the largest change to Firefox code in our history. Besides running faster and crashing less, E10S makes websites feel more smooth. Even busy pages, like Facebook newsfeeds, spool out smoothly and cleanly.

firefox tests
In Mozilla's own tests comparing memory usage for various browsers, it claimed that Firefox used significantly less RAM in macOS than both Safari and Chrome. The group has published an article on Medium explaining how the new E10s architecture works.

In one section titled "Why Chrome gets too hot when Firefox does not", Mozilla writes that Chrome's method of creating separate processes for each open tab can end up with each one consuming hundreds of megabytes of RAM, whereas Firefox reuses processes and content engines to limit memory usage.

By default, Firefox now creates up to 4 separate processes for web page content. So, your first 4 tabs each use those 4 processes, and additional tabs run using threads within those processes. Multiple tabs within a process share the browser engine that already exists in memory, instead of each creating their own.

Mozilla claims that Firefox's considerate memory usage means users with 8GB of memory or less can browse the web without the browser hogging resources, allowing them to do other things on their computer. Meanwhile, users with more than 8GB of RAM can bump up the number of content processes that Firefox uses to make it even faster.

To change the number of content processes Firefox uses, enter about:config in your address bar, and adjust the number for the dom.ipc.processCount setting (we'll be exposing a visible preference for this in an upcoming release).

Users can test out the claims by downloading Firefox 54 for free from the Mozilla website.

Top Rated Comments

gpat Avatar
110 months ago
Since when is 8GB considered low RAM for browsing?
Score: 18 Votes (Like | Disagree)
Sasparilla Avatar
110 months ago
Nice to see Mozilla is continues to update Firefox. I often use it in combination with Safari (which rules on the Mac) and don't want to see us reduced to a webkit (or webkit forked - Google) mono-culture.

For those interested here is a plug-in compatibility checker for Firefox. If the Firefox installation detects that one of your plugins isn't multi-process compatible it won't enable multi-processing for Firefox on your Mac.

https://addons.mozilla.org/en-US/firefox/addon/add-on-compatibility-reporter/

Adblock and Ghostery were okay for me - but the User Agent Switcher was not, part of Firefox (so I can run more than one instance of Firefox on my OS X desktop with different settings - i.e. different users).

Checking "about:config" in the address bar (say Yes), then go to "dom.ipc.processCount" in the address bar to see how many multiprocess threads you're allocated. Should be 4 if everything is good.

Because of my OSX User Agent Switcher conflict I only have 1 for my processCount. The Windows version of task switcher is compatible, BTW. Mozilla needs to update the OS X version (and probably Linux - they often share alot of code) of the User Agent Switcher to be compatible as well.
Score: 6 Votes (Like | Disagree)
Zirel Avatar
110 months ago
It uses less memory because only a smaller part of the page is rendered.

Safari uses a little bit more of memory, but when you scroll, it's already rendered while on Firefox you have to wait...

Safari is better, also much better performance in JavaScript.

(https://postimg.org/image/6e1t7xf65/)
Score: 6 Votes (Like | Disagree)
fokmik Avatar
110 months ago
firefox is dead, long live safari or chrome or even edge
Score: 4 Votes (Like | Disagree)
batchtaster Avatar
110 months ago
Those are not "Macs", but "Macbooks" on the Apple site.

..... I still feel like you're joking here. A MacBook is not a Mac. Right.....
If that's the case, then Firefox's memory usage on it is a non-issue, since it's not "a Mac" and therefore won't run the "Mac" version of Firefox.

Also, those are iMacs, not Macs. That's how it works, right?

I guess the Mac Pro is also not "a Mac", even though its name suggest it's a Pro version of a Mac.

Please inform Apple, as their website's "Mac" header ('https://www.apple.com/mac/') is apparently wrong.

When I buy "a Mac" in your world, which model do I get?

Attachment Image
Score: 3 Votes (Like | Disagree)
miknos Avatar
110 months ago
So basically ALL Macs since none of them comes with more than 8GB!
Score: 2 Votes (Like | Disagree)

Popular Stories

Apple Logo Spotlight

Report: Apple to Launch These New Products in 2026

Sunday November 2, 2025 5:34 am PST by
Apple is planning to launch at least 15 new products in 2026, according to Bloomberg's Mark Gurman. Gurman outlined what to expect from Apple in 2026 in the latest edition of his "Power On" newsletter. He said the company is heading "into one of its most pivotal years in recent memory," with the rollout of major new Apple Intelligence features, intense regulatory pressure on the App Store,...
Apple Intelligence General Feature 2

New Version of Siri to 'Lean' on Google Gemini

Sunday November 2, 2025 6:06 am PST by
In his "Power On" newsletter, Bloomberg's Mark Gurman today provided an update on the status of Apple Intelligence and the plans for it in 2026. Apple is still planning to roll out its revamped version of Siri around March of next year. The release should be accompanied by the release of a new smart home display product with speaker-base and wall-mount options. A new Apple TV and HomePod...
HomePod mini and Apple TV

New Apple TV and HomePod Mini Likely Launching Soon

Sunday November 2, 2025 5:49 am PST by
A new Apple TV and HomePod mini could launch as soon as this month, Bloomberg's Mark Gurman today suggested. In today's "Power On" newsletter, Gurman said that Apple retail stores are planning an overnight refresh on the evening of November 11, where changes will be made after closing, such as refreshing displays and placing new products for the following day. The timing of the overnight...
iOS 26

Apple Releases iOS 26.1 With Liquid Glass Toggle, Slide to Stop Alarm, New Apple Intelligence Languages and More

Monday November 3, 2025 1:11 pm PST by
Apple today released iOS 26.1, the first major update to the iOS 26 operating system that came out in September, iOS 26.1 comes over a month after iOS 26 launched. ‌iOS 26‌.1 is compatible with the ‌iPhone‌ 11 series and later, as well as the second-generation ‌iPhone‌ SE. The new software can be downloaded on eligible iPhones over-the-air by going to Settings > General >...
iOS 26

iOS 26.1 Available Now With These 8 New Features

Monday November 3, 2025 5:54 am PST by
Following more than a month of beta testing, Apple released iOS 26.1 on Monday, November 3. The update includes a handful of new features and changes, including the ability to adjust the look of Liquid Glass and more. Below, we outline iOS 26.1's key new features. Liquid Glass Toggle iOS 26.1 lets you choose your preferred look for Liquid Glass. In the Settings app, under Display...
Early Black Friday Deals 2

The Best Early Black Friday Apple Deals

Sunday November 2, 2025 10:04 am PST by
We're officially in the month of Black Friday, which will take place on Friday, November 28 in 2025. As always, this will be the best time of the year to shop for great deals, including popular Apple products like AirPods, iPad, Apple Watch, and more. In this article, the majority of the discounts will be found on Amazon. Note: MacRumors is an affiliate partner with some of these vendors. When ...
apple one  cpqesecbv342 upscaled feature

Apple One Gets New Colorful Logo Following Apple TV Rebrand [Updated]

Monday November 3, 2025 3:22 pm PST by
Apple updated the logo and name for its Apple TV streaming service today, and it looks like Apple One might be next. On the revamped Apple TV website, there's a new, more colorful Apple One logo available. The logo features an Apple icon that's split into six slices, and each slice includes the color that Apple uses for one of the services included in Apple One Premium. Apple One is...