System performance refers to how well a computer or network operates in terms of speed, efficiency, and reliability. It is often measured by metrics such as response time, throughput, and resource utilization. High system performance means that tasks are completed quickly and resources are used effectively, leading to a better user experience. Factors affecting system performance include hardware specifications, software optimization, and network conditions. Upgrading components like the CPU or RAM can enhance performance, while regular maintenance and updates to software can prevent slowdowns. Monitoring tools can help identify bottlenecks and areas for improvement.