I am running ESXi 5.5 under the evaluation license and can not configure a VM with more that 8 cores, and the host system has 16 cores available. Is this due to a evaluation license restriction?
YES...It’s not often that one would need to run at home 8 vCPU VMs
While in evaluation (i.e. no license key entered) you are basically running the Enterprise Plus edition which isn't limited to 8 vCPUs. I guess you are running the free Hypervisor edition which has this limitation.
André