Q. What is VMMQ?
A. New to Windows Server 2016 Hyper-V is VMMQ which continues to build on the investments in RSS and VMQ in previous versions. VMMQ stands for Virtual Machine Multi-Queue. Previously a single VM could be allocated a single VMQ (which is an I/O queue on the NIC and helps speed up performance) and this queue would be affinitized to a single processor core. Today network adapters have huge numbers of queues, often more than VMs running on the box. While vRSS enables multiple cores in the VM to process traffic the traffic still originates from the single queue. With VMMQ multiple queues are allocated to a single VM with each queue affinitized to a core in the VM. Even the default queue in Hyper-V (which is used by VMs with out their own queue) utilizes multiple queues now. The distribution of traffic between queues is performed by the NIC avoiding overhead on the CPU.
Remember that even with VMMQ the VM must have multiple cores (vCPUs) to enable each queue allocated to be bound to a specific core.