I have a Dell laptop running Windows 11 with 16 GB of RAM. Task Manager consistently shows memory usage around 95% or higher, even when I only have a few Firefox tabs open and no other obvious programs running. When I add up the memory usage shown for individual processes, the total is nowhere near 16 GB. What could be consuming the missing memory, and how can I diagnose it?
4 Answers
If the process totals are much lower than the actual memory usage, a driver or another kernel-level component could be responsible. Try starting Windows in Safe Mode and see whether memory usage remains unusually high. If it drops, review recently installed drivers, utilities, and hardware-related software, then update or remove the likely culprit.
Firefox itself may not be the main issue, but extensions can leak memory. Update Firefox, confirm you are using the 64-bit version, then disable every extension and restart the browser. If usage improves, re-enable extensions one at a time to identify the problem one.
Check Resource Monitor rather than relying only on the basic Task Manager list. Its memory breakdown can show standby, modified, kernel, driver, and hardware-reserved memory that may not appear as a normal application process. Windows does use otherwise-free RAM for caching, but that memory should be released when an application needs it, so consistently high usage with slowdowns deserves further investigation.
A high percentage alone does not necessarily mean something is broken—Windows keeps data cached to improve performance and can reclaim it when needed. Check whether the computer is actually slowing down, paging heavily, or showing high disk and CPU activity. Restart if Windows updates are pending, make sure the system drive is not nearly full, and observe whether the usage eventually falls.

It is also worth checking whether a recent Windows or driver update happened around the time the problem began. A memory leak can make usage climb gradually even when no single application looks large.