Chris Wahl from the Wahl Network comments:
Hyper-Threading (HT) is sometimes viewed as the mystical voodoo that enables you to have twice as many logical cores on your physical CPU. Occasionally, the voodoo is abused when sizing the quantity of virtual machine vCPUs for a workload. After all — if the vSphere host says I have 8 logical processors available to me, can’t I use all of them for a single VM and its vCPUs? Hyper-Threading definitely has its advantages, but to properly use the technology in your vSphere host, you must understand a little of the basics.
Chris lays bare the differences between real processor cores and hyperthreading and how each works in VMware.
Read more at: Hyper-Threading Gotcha with Virtual Machine vCPU Sizing