Memory leak – when the Available MegaBytes (memory\% available Mbytes) for the system has exceeded the threshold, system performance may be significantly diminish, this results in low OS and applications performance. End users will usually complain about slow computer performance and you probably get a help-desk call like: ‘My computer is running slow’, or server is running slow.

Memory leaks can be caused by:

• Too many applications running simultaneously on the computer.
• An application may be leaking memory over time.

To view the history for the memory\% available Mbytes, start memory available Mbytes in performance monitor or event task manager\performance.

If your system has been correctly provisioned with physical memory and application load but continually exceeds the available physical memory threshold over time, it is probably due to that an application is leaking memory over time.

To identify an application that is leaking memory, do the following:

Open ‘Performance monitor’ and monitor the following systemwide performance counters over time:

• Paging file\% usage
• Memory\Pool nonpaged bytes
• Memory\Pool paged bytes

If any one of these counters continuously increases over time, it is likely that an application is leaking memory.

The specific application can be identified by monitoring the following counters for each running process:

• Process\Page file bytes
• Process\pool nonpaged bytes
• Process\pool paged bytes
• Process\Private bytes
• Process\thread count

If you notice a consistent and significant increase in any of these counters, check with the application vendor for support.