Browser.cache.memory.capacity

| Cache Type | Location | Persistence | Key Preference | |------------|----------|-------------|----------------| | Memory cache | RAM | Session only | browser.cache.memory.capacity | | Disk cache | Hard drive/SSD | Persistent across sessions | browser.cache.disk.capacity | | App cache (obsolete) | Disk | Persistent | browser.cache.offline.capacity |

To understand this setting, you must first understand that Firefox maintains two primary types of cache: Browser.cache.memory.capacity

The preference browser.cache.memory.capacity determines the . Specifically, it sets the maximum amount of RAM (in kilobytes) that Firefox is allowed to use to store cached web content. | Cache Type | Location | Persistence |

| System RAM | Operating System | Recommended browser.cache.memory.capacity | Reasoning | | :--- | :--- | :--- | :--- | | | Windows 10/11, Linux | 0 or 65536 (64 MB) | Preserve RAM for OS; disk cache is safer. | | 8 GB | General Use | -1 (Auto) or 131072 (128 MB) | Auto mode works best here. | | 16 GB | Gaming / Heavy Tab User | -1 (Auto) or 262144 (256 MB) | 256 MB is a safe, performant manual value. | | 32 GB | Development / Content Creation | 524288 (512 MB) to 1048576 (1 GB) | You have headroom. Store complex web apps fully. | | 64 GB+ | Workstation / Server | 2097152 (2 GB) | Only if you rarely close Firefox. Monitor memory usage. | | | 8 GB | General Use |