Browser.cache.memory.capacity New! Jun 2026

To revert:

To fully optimize your Firefox memory and storage pipeline, consider pairing your adjustment with these complementary settings inside about:config :

: Must be set to true (default) for capacity to work.

When you visit a website, Firefox stores some of the content in memory (RAM) so that if you revisit the same page or navigate to a similar page, it can load faster. This is known as caching. The browser.cache.memory.capacity parameter determines how much memory is allocated for this caching. Browser.cache.memory.capacity

If you have a high-end PC with 16 GB, 32 GB, or more of RAM, allocating more memory to Firefox (e.g., 512 MB or 1 GB) can yield performance gains. A larger cache keeps more data ready for instant access, reducing page redraw times and speeding up navigation through heavy websites. When to Decrease or Disable the Value

The configuration setting is an advanced preference in Firefox-based browsers (accessible via about:config ) that manually determines the maximum amount of system RAM used for the memory cache. Core Functionality

If the preference exists, double-click it (or click the pencil icon) to edit the value. To revert: To fully optimize your Firefox memory

Adjusting this setting can have significant effects on browser performance:

Depending on your needs, you can set this integer to various values:

Modifying this value can have unintended consequences, such as: The browser

In the search box, type: browser.cache.memory.capacity .

Internet browsers face a continuous balancing act between speed and system resource consumption. Every webpage loaded contains images, scripts, style sheets, and multimedia assets. To avoid re-downloading these assets during navigation, browsers store them temporarily in a cache.

The value of browser.cache.memory.capacity is measured in kilobytes (KB). When Firefox starts, it allocates a portion of memory based on this value. As you browse the web, Firefox stores cache entries in this allocated memory. When the cache grows, Firefox uses a least-recently-used (LRU) algorithm to evict older cache entries to make room for new ones.