Phil Windley, former CIO of Utah, had a student do a report on ESX server performance. He reports the following findings from the student:
- Single CPU virtual machines scale better than virtual machines using Virtual SMP.
- Hyper-Threading increases throughput if there are a large number of virtual CPUs, but makes no difference if the number of virtual CPUs is less than or equal to the number of physical CPUs.
- Do not allocate excessive resources to virtual machines. Additional resources may hurt performance.