This boolean preference acts as the master switch for the memory cache. It must be set to for the memory cache to function at all. The default is true . If you ever need to completely disable memory caching (for debugging, for example), set this to false .
In recent versions of Firefox, the transparency of this setting has sparked debate. While the parameter can still be manually added or modified via the Advanced Preferences (about:config) page
When disk cache is disabled, the "disk" section in about:cache may actually display memory cache entries, which can be confusing. This is because Firefox`s internal caching architecture sometimes routes requests through the disk cache interface regardless of where data is actually stored. Browser.cache.memory.capacity
can be much larger (gigabytes, if you wish) and persists across browser sessions, but it is slower to read from and write to. Frequent disk writes—especially on older SSDs—can theoretically shorten the drive’s lifespan, although for modern SSDs this is rarely a practical concern for normal users.
"If we don't drop data," DocShell screamed, "the whole process is going to crash! The User will lose the form data in Tab 1!" This boolean preference acts as the master switch
Enter 32768 (Standard default ceiling for mid-range systems). 64 Megabytes (MB): Enter 65536
: It stores copies of recently visited site data (like images and scripts) directly in your RAM rather than on your disk. This allows for near-instant retrieval when you hit the "Back" button or revisit a page in the same session. If you ever need to completely disable memory
Is your browser acting like a resource hog? If you’ve ever opened your Task Manager and felt a pang of betrayal seeing Firefox or a similar browser devouring gigabytes of RAM, you aren't alone. One of the most effective under-the-hood tweaks involves a specific hidden setting: 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.
The User, sitting in the physical world, groaned as their mouse cursor stuttered. The smooth scrolling on the art gallery turned into a jerky slideshow.
Understanding Browser.cache.memory.capacity: Optimize Firefox Ram Usage