Available Memory


  • If you open up task manager on a 2008 server/Win 7 computer, available MBytes matches the value in the Performance tab, Physical Memory -> Available.  What people generally look at is the "Physical Memory: XX%" down at the bottom.  This is different.


    "Regardless of how much memory your system has, the question is, is it enough? Unfortunately, there's no hard and fast rule that allows you to know with certainty. There is a general guideline you can use that's based on monitoring the system's "available" memory over time, especially when you're running memory-intensive workloads. Windows defines available memory as physical memory that's not assigned to a process, the kernel, or device drivers. As its name implies, available memory is available for assignment to a process or the system if required. The Memory Manager of course tries to make the most of that memory by using it as a file cache (the standby list), as well as for zeroed memory (the zero page list) (...) [and a Windows] feature prefetches data and code into the standby list and prioritizes it to favor data and code likely to be used in the near future.


    If available memory becomes scarce, that means that processes or the system are actively using physical memory, and if it remains close to zero over extended periods of time, you can probably benefit by adding more memory. There are a number of ways to track available memory. On [Windows Vista/2008/7/2008 R2], you can indirectly track available memory by watching the Physical Memory Usage History in Task Manager."

    Between Available MBytes and % committed bytes in use, you can get a pretty good idea of your computers memory utilization.

    • Marked as answer by Vivian Xing Monday, July 4, 2011 9:13 AM
    Wednesday, June 29, 2011 2:31 PM