Browser.cache.memory.capacity Jun 2026

If Firefox is consuming too much RAM, setting a lower manual limit (like ) can prevent it from "ballooning" over time ( MozillaZine SSD Longevity: Some users disable the disk cache browser.cache.disk.enable ) and increase the memory cache instead to reduce physical writes to their SSD ( openSUSE Forums

| Value | Meaning | |-------|---------| | -1 | Firefox automatically manages the cache. | | 0 | Disabled. No memory caching. Drastically slows down session navigation. | | 65536 (64 MB) | Conservative fixed limit. | | 131072 (128 MB) | Moderate fixed limit. | | 262144 (256 MB) | High fixed limit (rarely needed). |

A: Yes. Each Firefox profile has its own about:config settings, including this preference.

| Desired Size | Value (KB) | |--------------|------------| | 25 MB | 25600 | | 50 MB | 51200 | | 75 MB | 76800 | | 128 MB | 131072 | | 256 MB | 262144 | Browser.cache.memory.capacity

When you visit a website, the browser downloads various resources, like images, scripts, and stylesheets. These resources are stored in the cache, which is divided into two parts:

The browser sets browser.cache.memory.capacity to a percentage of total system RAM (e.g., 5–10%), updating dynamically on system changes (e.g., after hibernation, new RAM installed).

This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. If Firefox is consuming too much RAM, setting

When a user loads a webpage, the browser downloads resources (HTML, CSS, Images). To display the page, the browser must "decode" these files (e.g., turning a compressed JPG into raw pixel data).

If you`re running Firefox on a system with limited RAM (4 GB or less):

: Search for browser.cache.memory.capacity . If it doesn't exist, right-click (or click the "+" button), choose New > Integer , and name it exactly as above. Drastically slows down session navigation

In the architecture of modern web browsers—specifically those based on the Gecko engine like Firefox—the parameter browser.cache.memory.capacity

Ensure browser.cache.memory.enable is set to for this to take effect. Why Adjust This Setting?