Mastering VMware vSphere 6.5

Processor metrics

Statistically, most servers have low overall CPU usage (< 25%), which is the main reason why server virtualization is so effective and used for server consolidation. But you have also to consider the peaks, which could be near 100% in some cases and, depending on how frequent they are, how long in duration, and how they are correlated, could become critical for the virtual infrastructure sizing.

CPU is usually overcommitted and depending on the workload, a 4:1 ratio between virtual and physical resource could be a reasonable target if you don't have CPU-intensive (or CPU-bound) workloads. Note that the ratio should be calculated on the physical (real) cores, not the logical processors that VMware ESXi sees, because hyper-threading ...