After booting Windows 11, my memory usage gradually climbs to around 80–95% of my 12 GB of RAM, even when the computer is idle or only Chrome is open. Task Manager and Resource Monitor do not show any single application using enough memory to explain this, and the usual cached-memory section does not appear unusually large. I have run offline and regular malware scans with several antivirus tools, but they found nothing. The system has also become noticeably slower, and sometimes I cannot even open another Chrome tab. My RAM consists of mixed 8 GB and 4 GB sticks; I know that is not an ideal configuration, but games and stress tests performed better with both installed than with only the 8 GB stick. What could be consuming the missing memory, and how can I identify it?
3 Answers
Using an 8 GB stick together with a 4 GB stick is not ideal, but it would not normally explain unexplained RAM usage or make Windows consume nearly all available memory. The mixed capacity can affect memory-channel behavior, but it is more useful to troubleshoot the memory breakdown or a possible driver leak first.
Windows normally uses otherwise-unused RAM for caching frequently accessed files and applications, but that cache should be released when another program needs memory. If the cache is small while overall usage is very high and the system is struggling, this is not simply normal prefetching. Check the detailed memory categories and consider using Resource Monitor or RAMMap to find which type of memory is growing.
A screenshot of the Memory tab in Task Manager would help, especially the breakdown for In use, Committed, Cached, Paged pool, Non-paged pool, and Hardware reserved. If the applications list does not account for the usage, the problem may be a driver memory leak, compressed memory, or unusually large kernel pool usage rather than a normal application.
The computer is running Windows 11. After a fresh boot, memory usage can remain around 95% even with only Chrome open.

The mixed configuration was not causing this before, and the performance issue is noticeable even during games, so I am not convinced the RAM sticks alone explain it.