Thanks. I just also read the following link CPU Virtualization Basics and it says the following. It appears if I configure all 4 VMs to have 4 cores each, then VM1, VM2, and VM4 will have access to the 4 cores 14% of the time per VM, and VM3 will have access to the 4 cores 57% of the time.
When CPU resources are overcommitted, the ESX/ESXi host time-slices the physical processors across all virtual machines so each virtual machine runs as if it has its specified number of virtual processors. When an ESX/ESXi host runs multiple virtual machines, it allocates to each virtual machine a share of the physical resources. With the default resource allocation settings, all virtual machines associated with the same host receive an equal share of CPU per virtual CPU. This means that a single-processor virtual machines is assigned only half of the resources of a dual-processor virtual machine.
However, your following statement is quite interesting. While this wouldn't be an issue if I abandon ESXi and just install all the processes running on the 4 VMs on one single OS (ie not using VMware), it does appear to be an issue if I want to use ESXi. Can you provide a URL where I can read more about this? I have read through a few docs but don't recall having seen this.
If a VM has multiple cores, the VM will not be able to process an instruction unless it can access the number of cores that it was allocated, simultaneously. So, unless you really NEED multiple cores, it is not recommended to allocate more than one.
