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
84 months ago
Since when is 8GB considered low RAM for browsing?
Score: 18 Votes (Like | Disagree)
Sasparilla Avatar
84 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
84 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
84 months ago
firefox is dead, long live safari or chrome or even edge
Score: 4 Votes (Like | Disagree)
batchtaster Avatar
84 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
84 months ago
So basically ALL Macs since none of them comes with more than 8GB!
Score: 2 Votes (Like | Disagree)

Popular Stories

iOS 17

26 New Things Your iPhone Can Do With Next Month's iOS 17.2 Update

Wednesday November 22, 2023 10:57 pm PST by
Apple made the first beta of iOS 17.2 available to developers in October. Since then we've seen two more betas, and with each iteration Apple continues to add more new features and changes, many of which users have been anticipating for quite a while. Below, we've listed 26 new things that are coming to your iPhone when the finalized version is publicly released in December. 1. Help You...
Apple Watch Series 9

5 Reasons to Wait for Next Year's Apple Watch

Friday November 24, 2023 3:46 am PST by
With all the discounted deals on Apple tech currently available, you might be thinking about upgrading your Apple Watch or buying one for the first time. But if your current smartwatch is doing its job just fine and it's only the idea of a good deal that's piqued your interest, it could be worth holding out until next year when Apple unveils its latest and greatest version. There are already ...
General Black Friday Deals 2022 Green

40+ Apple Black Friday Deals Still Available for AirPods, iPhone, iPad and More

Friday November 24, 2023 5:01 am PST by
Black Friday 2023 has officially ended, but we're still tracking some of the best deals of the year on Apple products like AirPods, iPad, iPhone, MacBook, and many more. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment, which helps us keep the site running. Specifically, in this article we're...
Cyber Monday Deals Feature 2022

40+ Apple Cyber Monday Deals for AirPods, iPad, Apple Watch, and More

Sunday November 26, 2023 9:47 am PST by
Cyber Monday has taken the place of Black Friday, and you'll find many of the same deals still around today. This includes dozens of record low prices on Apple products like AirPods, iPad, Apple Watch, MacBook, iPhone, and more. Note: MacRumors is an affiliate partner with some of these vendors. When you click a link and make a purchase, we may receive a small payment, which helps us keep the...
ipad mini 2021 youtube

What to Expect From the Next iPad Mini Later in 2024

Friday November 24, 2023 1:00 pm PST by
Over 800 days have passed since Apple last updated the iPad mini, as outlined in the MacRumors Buyer's Guide. Fortunately, a new iPad mini is rumored to be released next year, and we have outlined what to expect from the device below. Apple released the current iPad mini in September 2021, with new features at the time including a larger 8.3-inch display, a USB-C port, a Touch ID power...