The absence of benchmarks for Web sites with dynamic content hasbeen a major impediment to research in this area. We describe three benchmarks for evaluating the performance of Web sites with dynamic content. The benchmarks model three common types of dynamic-content Web sites with widely varying application characteristics: an online bookstore, an auction site, and a bulletin board. For each benchmark we describe the design of the database, the interactions provided by the Web server, and the workloads used in analyzing the performance of the system. We have implemented these three benchmarks with commonly used open-source software. In particular, we used the Apache Web server, the PHP scripting language, and the MySQL relational database. Our implementation is therefore representative of the many dynamic content Web sites built using these tools. Our implementations are available freely from our Web site for other researchers to use. We present a performance evaluation of our implementations of these three benchmarks on contemporary commodity hardware. Our performance evaluation focused on finding andex plaining the bottleneck resources in each benchmark. For the online bookstore, the CPU on the database was the bottleneck, while for the auction site and the bulletin board the CPU on the front-end Web server was the bottleneck. In none of the benchmarks was the network between the front-end and the back-end a bottleneck. With amounts of memory common by today's standards, neither the main memory nor the disk proved to be a limiting factor in terms of performance for any of the benchmarks.