The most crucial aspect of performance is speed, which refers to how quickly the software responds to user inputs, processes data, and displays results. This is often indicated as response time, and it is the aspect that the end user directly experiences.

However, there are other aspects that come into the picture. Performance can be divided into several categories. Another such category is scalability. This refers to the software’s ability to maintain or improve performance as the load increases. This increase in load can be caused by an increase in the number of users, number of concurrent tasks, or data volume.

The above two performance aspects, speed and scalability are related to the end-user experience. There are also aspects that are more of a technical nature.

The first one is throughput. Throughput is the number of tasks or requests that the software can handle simultaneously or in a given timeframe. This is often referred to as transactions per second.

Another one is resource usage; this indicates how efficiently the software uses system resources, such as CPU, memory, disk I/O, and network bandwidth. These technical aspects are not directly linked to the experience of end users but can be used by development teams to tweak the performance.