Browser.cache.memory.capacity Exclusive Jun 2026
Enter 262144 (Ideal for power users with 32 GB+ RAM who keep hundreds of tabs open).
Firefox will display a warning: "This might void your warranty!" Click "Accept the Risk and Continue."
Modifying this setting allows you to fine-tune how much memory Firefox allocates for temporary web assets, helping you balance browsing speed with system performance. What is Browser.cache.memory.capacity?
If you set browser.cache.memory.capacity to 102400 (100 MB) and about:cache shows "Maximum storage size: 102400 KiB," your change was successful. Browser.cache.memory.capacity
Do not rely on synthetic benchmarks. Run a real test:
By default ( -1 ), Firefox caps memory cache aggressively. If Firefox is using 4 GB of RAM, it's due to web content (heavy JavaScript, video streams, leaked memory in tabs), not the memory cache.
By default, modern versions of Firefox handle memory cache scaling automatically based on a percentage of your total available system memory. However, this parameter can be explicitly overridden using specific integers: Firefox/Tweaks - ArchWiki Enter 262144 (Ideal for power users with 32
Dictates whether Firefox is allowed to use RAM caching at all. Ensuring this is set to true is required for your capacity adjustments to mean anything. browser.cache.disk.enable Type: Boolean (True/False)
More cache isn't always better. If you set the capacity too high, you might starve other applications of memory, leading to system-wide lag. Start with a moderate increase, restart your browser, and see how it feels.
A: Firefox will evict older or less frequently accessed items from the cache to make room for new ones. Performance may degrade if the cache is too small for your browsing patterns. If you set browser
: Tells the browser to automatically determine the capacity based on your system's total physical RAM.
The following table shows how Firefox historically determined memory cache size based on available RAM:
browser.cache.memory.capacity is a configuration preference in Firefox-based browsers that determines the maximum amount of
