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System sizing

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

System sizing

Most computer users can be placed into one of three categories:

  • Light users. A light user typically runs one program at a time--for example, a word processing program or a line-of-business program.

  • Structured task users. A structured task user simultaneously runs two or more programs but does not frequently switch between programs. This user runs programs whose data-processing demands on the system are not heavy--for example, productivity programs such as word processing and an Internet browser.

  • Power users. A power user is a more sophisticated user who runs three or more programs, and often has several active at the same time. A power user runs programs whose data processing demands on the system are heavy, such as detailed queries on large databases.

When determining how powerful your servers need to be, consider the types of users who will be using them. Light users place the lightest load on computational resources while power users consume the most computational resources. Also consider the types of programs your server runs. Keep in mind that a terminal server shares executable resources between individual users, just as any of the Windows Server 2003 family operating systems shares executable resources (.dll, .exe, and so on) between individual programs. As a result, the memory requirements for additional users running the same program are typically less than the requirements for the first user to load the application.

For adequate performance, a terminal server requires a Pentium or higher processor. A terminal server requires a minimum of 128 MB RAM, plus additional RAM for each user to support running each user's programs on the server. An additional 10 MB RAM is recommended for each light user and up to 21 MB RAM for each power user.

In general, processor and memory requirements scale linearly: You can support double the number of users on a multiprocessor-capable Pentium system by doubling the number of processors and doubling the amount of memory. Purchasing a system that supports multiple processors, even if you initially purchase only one processor, allows you to add capacity easily as your requirements grow.

Performance can vary depending on the programs you run on a terminal server. To judge the processing power and RAM required for each user, test your system by running the programs you use.

The bus architecture in single and multiprocessor systems also affects system performance. The ISA (AT bus) architecture is low bandwidth and is not recommended for a terminal server. Use a higher-performance bus, such as EISA, MCA, PCI, PCI-X, or InfiniBand for best performance. All of these buses support the sustained high data transfer rates typically required when running Terminal Server.

Peripherals can affect the performance of a terminal server. For more information, see Peripherals that affect performance.