When you buy a capacity, you get a predefined number of v-cores, as listed in Capacities and SKUs.
By displaying your capacity's CPU usage levels, the Power BI Premium Utilization and Metrics app helps you understand how your capacity is performing. To provide a simple way of measuring your capacity's performance, the app reports CPU usage for the number of v-cores your capacity has. Power BI makes throttling and autoscale decisions based on the data that's displayed in the app.