System requirements for each element of your system vary depending how you use it. The numbers in this guide are suggestions only, not definitive recommendations.
You should base the minimum configuration of any system on expected peak load. Typically a configuration running all elements of the application on a single server spends 95% of its time idle and 5% of its time trying to keep pace with the resource demands. If you expect your system to perform an operation that could run create, modify or delete rules on tens or hundreds of thousands of business objects, your system requirements may be much higher. See System Basics for more specific hardware recommendations.