Firefox 157: Return of Compact Mode, Hardware AV1, and New Design Without Performance Loss

In this release, the Mozilla team combined a visual interface refresh with important technical optimizations for hardware acceleration.

1. What This Release Is About: Why Mozilla Is Updating the Interface

Mozilla officially rolled out Firefox 157, marking a major interface overhaul for the browser on desktop and mobile platforms. The update brings fresh color schemes, redesigned icons, and themes.

The developers’ main goal is to make the browser look modern (“current, but not generic”) while preserving its recognizable identity. A critical aspect for everyday use: the visual redesign is optimized so it does not negatively impact performance or rendering speed. At the same time, the browser strictly maintains its core principles—independence, open source code, and built-in privacy protection.

2. Compact Mode: Setup and Practical Benefits

One of the most practical additions is the official return of Compact Mode. When working on laptops with small screens, the standard wide toolbars cut into usable workspace. Compact Mode shrinks tab and toolbar sizes, freeing up maximum space for web pages.

How to Enable Compact Mode

Method 1: Through the Graphical Interface

1. Open Settings (about:preferences) or the theme selector panel.
2. Select the compact density for interface elements.

Method 2: Through Advanced Settings (about:config)

1. Type about:config into the address bar and press Enter.
2. Confirm the warning about accessing advanced settings.
3. In the search field, find the parameter: browser.compactmode.show.
4. Switch its value to true.
5. Then find the interface density parameter: browser.uidensity.
6. Set the numeric value to 1 (where 0 is standard, 1 is compact, 2 is touch).

3. Technical Breakdown: Hardware AV1 Decoding on GPU

From a technical standpoint, the key improvement in Firefox 157 is support for hardware AV1 codec decoding. Specifically, hardware AV1 is used for WebRTC video calls and media streams on compatible devices.

[Software Decoding]: CPU -> 80-100% Core Load -> Frame Drops -> Battery Drain & Heat
[Hardware Decoding]: GPU (ASIC) -> Dedicated Video Engine -> 0% CPU Load -> Power Efficiency

Sysadmin Analysis of Efficiency

• Reduced CPU/GPU Load: With software AV1 decoding, the central processor is forced to handle heavy video streams using general-purpose compute cores. A hardware decoder offloads the stream to specialized silicon blocks on the graphics card (Intel Xe/Arc, NVIDIA RTX 30/40+, AMD Radeon RX 6000+), significantly reducing system overhead.
• Eliminating Frame Drops: When watching 4K/8K video on YouTube or during WebRTC conferences, the processor does not hit throttling, which removes audio-video desync and video freezes.
• Extending Laptop Battery Life: Offloading computational work from the CPU reduces platform power consumption and heat output, increasing battery runtime.

4. Safe Update and Clean Installation Without Telemetry

Firefox 157 introduces an important security tool: the browser displays explicit warnings in the site information panel and settings if Encryption Key Logging is enabled. This signals that third-party software on the computer may be intercepting and reading encrypted web traffic.

Clean Update and Configuration Steps

• Standard Update: Navigate to Menu → Help → About Firefox to download the official patch in the background.
• Download Clean Installer: Download the distribution only from the official Mozilla site, avoiding third-party repacks.
• Disable Telemetry and Firefox Suggest:
  1. Open about:preferences#privacy.
  2. In the “Firefox Data Collection and Use” section, uncheck the boxes for sending technical information.
  3. In the Firefox Suggest block, disable unused contextual suggestions in the address bar.

Admin Tip: If you manage a fleet of applications centrally, you can update browsers and system utilities in batch mode—read more in our guide how to update all Windows programs in one click using UniGetUI.

Frequently Asked Questions About Firefox 157 (FAQ)

How Do I Restore Compact Mode in Firefox 157?

If the option is hidden in the standard appearance menu, open the configuration at about:config, find the directive browser.compactmode.show and set the value to true. Then switch the interface density browser.uidensity to 1.

Which Graphics Cards Support Hardware AV1 in Firefox 157?

Hardware media stream decoding is available on NVIDIA GeForce RTX 30/40 series and newer, AMD Radeon RX 6000+, as well as Intel Iris Xe integrated graphics (starting with 11th-generation Core processors) and Intel Arc accelerators.

Where Can I Download the Official Distribution Without Third-Party Add-ons?

Download the clean installation package directly from the official Mozilla Firefox website, avoiding third-party software aggregators.