Topic Last Modified: 2006-04-28

The Microsoft® Exchange Server Analyzer Tool has determined that the user memory performance counters are above the threshold of what is considered healthy for the Exchange server. The Exchange Server Analyzer queries the Available Mbytes performance counter and the Memory Pages/sec counter under the Memory performance object. When the server is low on memory or has high paging, it indicates a memory bottleneck.

The Available MBytes performance counter shows the amount of physical memory in megabytes (MB) immediately available for allocation to a process or for system use. The amount of memory available is equal to the sum of memory assigned to the standby (cached), free, and zero page lists.

Memory Pages/sec performance counter indicates the rate at which pages are read from or written to disk to resolve hard page faults. As the server uses memory and free memory becomes scarce, the operating system starts trimming the working set of the process and using the page file more aggressively. Using the page file affects overall performance because disk operations take longer than memory operations. This counter is a primary indicator of the types of faults that cause system-wide delays. It includes pages retrieved to satisfy page faults in the file system cache. These pages are usually requested by applications. This counter should be below 1,000 at all times.

If the Exchange Server Analyzer finds that the Available Mbytes performance counter indicates less than 50 MB of memory is available or that the rate at which Memory Pages are being written or read to or from disk is greater than 1,000 pages per second, the Exchange Server Analyzer displays an error.

The following list describes how you can improve the performance of user space memory.

To address this issue
  1. Use the Microsoft Exchange Server Best Practices Analyzer Tool ( to verify that the memory settings for the server are configured appropriately.

  2. Remove superfluous software. To make more memory resources available for Exchange, remove any third-party software tools that perform monitoring functions or any type of non-essential service. The Performance snap-in (Perfmon.msc) can help you to understand how much memory applications are consuming.

  3. Run server maintenance tasks off peak times. Running maintenance tools (such as Eseutil) or tasks (such as mailbox management) during peak times can use memory that would otherwise be used by Exchange. As a best practice, run these tools and tasks during non-peak times or during low usage periods.

  4. Consider moving user mailboxes from the affected server to another server to reduce server load. For more information, see Move User Mailboxes to Another Server.

For More Information

For more information, see the following Microsoft resources: