Planning Processor (CPU) Needs

Microsoft Exchange Server needs enough processing power to handle requests from clients and other servers in the site and to handle optional services such as third-party gateways, connections to other sites, RAS servers, and file servers for client installations. If your I/O subsystem is fast and is not a bottleneck, and if you have enough memory to handle Microsoft Exchange Server services and other services, a fast processor improves performance.

Multiple processors can significantly increase a server's performance. However, some overhead is associated with using multiple processors. Although Microsoft Exchange Server is designed for maximum scalability across processors, performance will improve by adding a second or third processor. The more processors added, the smaller the incremental performance increases. Not all servers need multiple processors, and not all hardware can support multiple processors, so plan your choices accordingly.