Improving your VM performance in OpenStack: NUMA and CPU Pinning Memory has a large impact in the performance of your workload. This affirmation is specially true if your workload is running on a VM, so you must be careful with your memory and NUMA if your machine supports it. But wait! What is NUMA? In the past, processors had been designed as Symmetric Multi-processing or Uniform Memory Architecture machines, which means that all processors shared the same access to all memory available in the system.