Planning Memory Needs

Microsoft Exchange Server runs on a wide range of hardware configurations and makes the best use of physical memory. For optimal performance, your servers should have enough physical memory to avoid heavy use of the system page file. Because accessing the page file is much slower than accessing physical memory, increasing the amount of memory can greatly improve performance. However, other hardware resources, such as the CPU or I/O subsystem, may become bottlenecks as you increase physical memory.

The size of the Microsoft Exchange Server memory cache is adjusted automatically when you run the Performance Optimizer. By default, Microsoft Exchange Server uses all of the physical memory available. If you run other programs on your servers, you can restrict the amount of memory used by Microsoft Exchange Server.