Virtual SMP (vSMP) explained

Multiple processor cores can be combined into a single integrated circuit (often called a socket). For example, a dual-core processor (a processor with two cores) can provide almost double the performance of a single-core processor. Each core can have one or more logical CPUs that can be used independently by the ESXi CPU scheduler to execute virtual machines.

The vSphere Virtual Symmetric Multi-Processing (vSMP or Virtual SMP) technology enables the use of multiple processors inside a VM. This technology enables you to run resource intensive applications in VMs configured with multiple virtual CPUs. You can configure a VM with up to 64 virtual CPUs.