Q. When planning for Hyper-V performance should I use the number of logical processors or the number of cores?
A. In my experience for performance planning purposes it is best to base capacity based on the number of cores and not the number of threads (logical processors). This is also useful since the hypervisor also has to do work and the additional capacity of the processors enabled through hyper-threading can be utilized by the hypervisor saving the rest for the VMs.