I want to see how much of the RAM is being used by my system.

When I go to Task Manager -> Performance and look under "Physical Memory (MB)" section, it lists 4 terms which are:-

  1. Total
  2. Cached
  3. Available
  4. Free

What is the difference between 3 and 4 ? What is the meaning of second "Cached" ?

If available is the memory available to be used up, then out of 8GB installed on my system, I can see that only <=1GB is available to be used even when only Firefox browser "only one program" is running.

RAM Usage

  • Side note: Unless something has a memory leak, or you're running some heavyweight background processes (IIS/SQL/etc), that's pretty odd that you've got that little memory available/free. My system with Firefox and Outlook is running at 8142 Free, 1870 Cached, 5230 Available, 3990 Free, Uptime: ~1.5 days.
    – Chris S
    Dec 30, 2011 at 13:29

1 Answer 1


The "Available" category is the total of the Standby cache, Free memory and the Zeroed list.

Free pages - When a page is taken off of the Standby page list, it is moved to the Free page list. This page is in physical RAM. These pages are not associated with any process. When a process exits, all of its pages are then dumped onto this list. Typically, there is a very small to no amount of free pages hanging around physical RAM.

Standby pages - This is a page that has left the process' working set. This page is in physical RAM. A standby page is like a cache for virtual memory pages. It is still associated with the process, but not in its working set. If the process touches the page, it is quickly faulted back into the working set. That page also has one foot out the door. If another process or cache needs more memory, the process association is broken and it is moved to the free page list. Most of the pages in available memory are actually standby pages.


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