Data Metrics
The quantity and size of the data the system interacts with also has a great impact on the system's overall performance. As would be intuitive, systems that will have to deal with larger quantities of discrete data items (e.g. documents, database records, etc.) must do more actual work than systems that deal with smaller quantities. Also, systems that deal with data items of larger sizes (e.g. individual documents with sizes measured in multiple megabytes) must often perform more actual work than systems that deal in a similar quantity of smaller-sized data items.
This means that systems that interact with larger quantities and/or sizes of data will usually need to have more powerful hardware and/or different deployment and configuration (versus lower-load systems) to ensure optimal performance.