Analytics nodes, witness nodes, and cloud proxies have various hardware requirements for virtual machines and physical machines.
For information about the components to install on each server profile in your deployment, and the required hardware specifications, see the KB article vRealize Operations Manager Sizing Guidelines (KB 2093783).
CPU requirements are 2.0 GHz minimum. 2.4 GHz is recommended. Storage requirements are based on the maximum supported resources for each node.
vRealize Operations has a high CPU requirement. In general, the more physical CPU that you assign to the analytics cluster, the better the performance. The cluster will perform better if the nodes stay within a single socket.