A vCPU, or virtual CPU, is a unit of compute capacity assigned by a cloud provider to a virtual machine or container host. It does not always equal one physical processor core; instead, it represents scheduled access to CPU time on shared hardware. Cloud teams use vCPU counts to size instances for performance, cost, and scalability.
In cyber security, vCPU matters because many virtual firewalls, proxies, and inspection gateways are sold or licensed according to the instance size they run on. More vCPUs can mean higher throughput and more room for encryption, packet inspection, and logging, but also a larger bill. Attackers can pressure weakly sized defenses by generating traffic bursts that exceed the appliance’s CPU capacity, causing drops or latency. Defenders therefore test CPU headroom, scale-out behavior, and license limits before deploying controls in production.