What Is Firefox Quantum?

Mozilla's high-speed browser has some smart features

Firefox Quantum (previously known as Firefox) is a free, open-source web browser created by Mozilla. In addition to being very light, the Quantum browser, written using the Rust programming language, launched with a variety of new features, including an integrated pocket to save content on the fly, privacy enhancements like tracking protection, and two-click screenshots.

The overhaul didn't just make Firefox quicker and lighter on system resources—it also added a more modern, minimalist-style interface. Using the Photon design language, Mozilla's developers produced an intuitive browsing experience that displays more web content.

Firefox Is a Fast Multi-Process Browser

Before the update, Firefox used to run everything in a single process. If a website or web page were loading poorly, the entire browser would perform sluggishly. It also meant if a tab crashed, the whole browser would crash.

However, with Firefox Quantum, you can control how many processes the browser runs; by default, Quantum uses four processes to view and render web content. Most modern computers come equipped with a multi-core CPU, so the default setting works well for the average user.

To change the maximum number of processes Firefox uses, though, follow the steps below:

  1. Go to Tools.

  2. Select Options.

  3. Scroll down to Performance, then uncheck Use recommended performance settings.

  4. Check or uncheck Use hardware acceleration when available. This setting is optional. When enabled, Firefox uses your graphics card to display media-based web content.

  5. Expand the Content process limit drop-down menu, then select from 1 to 7.

    A screenshot of Firefox Quantum's performance settings

Quantum Browser Uses Less Memory Than Chrome

In addition to being twice as fast as Firefox 52, Quantum uses 33% less memory than Google Chrome.

A screenshot comparing the memory usage for Firefox Quantum and Chrome browser.

Running both browsers separately, with the same number of tabs open yielded results close to the claims made by Mozilla.

Firefox Quantum Offers Improved Privacy

The release of Quantum introduced the option to enable Tracking Protection while browsing normally. Previously, this option was only available in Private Browsing mode.

Tracking Protection blocks online trackers from logging your browsing behavior and habits. When enabled, a few adverts or web tools may not load or function correctly, but overall browsing speed and fluidity will improve. The option to add Exceptions and Change Block List is available for greater customization.

To turn on Tracking Protection:

  1. Go to Tools.

  2. Select Options.

  3. Select Privacy & Security from the left pane.

  4. Scroll down to Tracking Protection, then select Always.

    A screenshot of Firefox's tracking protection feature.

Take Screenshots Directly From the Address Bar

Firefox Quantum offers a built-in screen capture option accessible from the Page actions drop-down. Use the crop tool to select a specific section of the page, grab the visible portion, or take a shot of the entire page.

Take screenshots from the adress bar in Quantum browser.

Screen captures can be copied to the clipboard, saved locally, or uploaded to Firefox's cloud storage. To take a screen capture, open the vertical ellipsis menu on the far right side of the address bar, then select Take a Screenshot.

Automatically Restore Firefox Browsing Sessions

The option to restore previous browser sessions has been available for some time through the History menu. However, the feature to automatically restore your previous session on Windows startup was part of Firefox's 61.02 release. Although enabled by default, you can double-check if session restore is turned on by doing the following:

  1. Go to Tools.

  2. Select Options.

  3. Check or uncheck Restore previous session.

    A screenshot of Firefox's restore previous session option.

Older legacy add-ons (NPAPI plugins) are not supported by the browser anymore. Moving forward, Firefox will only work with WebExtensions, which, according to Mozilla, can accomplish nearly anything a plug-in can.