AMD required VeriTest conducting a performance comparison between its Opteron CPU and Intel Xeon when serving a virtualization platform. The platform choosed was VMware ESX Server 2.5 and results indicate AMD as the best CPU for this kind of tasks.
Quoting from the executive summary whitepaper:
AMD commissioned VeriTest, a division of Lionbridge Technologies, to conduct a competitive Web server performance study within a virtualized server environment.
We conducted this study by running performance tests on a virtualized AMD Opteron processor-based server environment versus a virtualized Intel Xeon processor-based server environment. We conducted the study by running a set of performance tests using PC Magazine WebBench 5.0.
To perform this study, AMD supplied VeriTest with one HP ProLiant DL585 AMD Opteron processor-based server and one IBM xSeries 445 Intel Xeon processor-based server. These servers were chosen because they were considered to be near-equivalent platforms from a configuration perspective. Both servers had quad-processor configurations, 16 GB of RAM, and four Intel 82543 Gigabit Ethernet Adapters. See Appendix A for additional server specifications details.
We used VMware ESX Server 2.5.0 as the server virtualization software. Virtualization software allows one to partition a single hardware server into multiple virtual machines, each with isolated set of virtual hardware including CPU, memory, disk and networking, and running an independent operating system. Virtualization software maps these multiple independent sets of virtual hardware to underlying server hardware, such as CPU, memory, and network resources, so that each virtual machine gets a share of the underlying hardware resources.