This is primarily done as insurance for peak traffic conditions, and a most of the time a large percentage of site capacity is unused. There is no qualitative relationship between service quality and over-provisioned components. Server Load Balancers can spread the incoming network load among front-end web servers.
Accelerators can speed-up or enhance individual server performance.
Network QoS managers can help avoid or manage network congestion. Until now no solution has existed to allow you to intelligently analyze and control your system components, and to manage your enterprise operation in a proactive, cohesive, and comprehensive manner. An understanding of capacity utilization is perhaps the most important requisite to deliver service quality. The enterprise must develop a strong quantitative understanding of the capacity utilization of their application infrastructure, how different services and user groups are utilizing capacity, how many customers that it can support, and the capacity headroom or risk that it is taking in running its operations. The enterprise needs to apply capacity where and when it is needed.