When modifying browser.cache.memory.capacity , users often interact with a related setting: browser.cache.memory.enable .
If you have a high-performance machine with 16GB or 32GB of RAM, Firefox’s default "conservative" automatic scaling might not be taking full advantage of your hardware. By increasing this value (e.g., to 512,000 for 500MB), you allow the browser to keep more complex web apps and high-resolution images in RAM, making back-and-forth navigation through tabs feel much snappier. The Case for Decreasing Capacity Browser.cache.memory.capacity
This article explains what this preference does, how it works, whether you should modify it, and how to do so safely. When modifying browser
It only makes repeat loading of the same page during your current session faster. Your initial page load is always limited by network speed. The Case for Decreasing Capacity This article explains