Windows 2003 64Bit can support a theoretical limitation of 16 exabytes or 2⁶⁴

·         Kernel Mode Address space - 8 TB

·         Paged Pool – 128GB

·         NonPaged Pool – 75% of RAM up to a maximum of 128 GB.

·         System Cache/PTEs - 1 TB regardless of physical memory.

As you can see, with 64bit Windows all of the previous memory constraints are blow out of the water.   For just this reason alone upgrading to a 64bit OS should be seriously considered.

Troubleshooting 32bit memory problems

For those who have legacy applications and 32bit hardware upgrading may not be an option. So in the following I will go over some tips and tools to identify memory bottlenecks a 32bit system.

Physical Memory Exhaustion - This is pretty much the straight forward if you are out of physical memory and the system is excessively paging to disk. More physical memory is most likely the answer.

Kernel Memory Exhaustion -  Memory problems in  kernel memory are a little more challenging to nail down.  Here are some of the signs:

Paged Pool & Nonpaged Pool

·         Sluggish or unresponsive user interface

·         Server has message or client processing failures

o   RPC Service Unavailable

o   Not enough Storage to process this command

·         Pool allocation failures:

System PTEs

·         Server fails to respond to I/O requests

·         Server fails to respond to network requests

·         Server has message or client processing failures

If you are experiencing these problems or other unexplained issues kernel memory could be your issue.

Your first stop should be the performance tab in Task Manager. From here you can quickly gauge if you are approaching the kernel memory limits of the system. Take a look at the Kernel Memory section and look at the amounts used by the page pool ( > 250MB or > 150 with /3GB ) and nonpaged pool( >200 or >100 with /3GB).  If we come up higher than these numbers further investigation is required.   We’ll start there next time.