A VPS offer is usually a vCPU count, RAM and disk. For a store it also matters how old the processor is, what clock it has, and whether the hypervisor gives the machine real time. A cheap “16 vCPU, 32 GB, NVMe” pack often sits on a Xeon from 2013 or 2015. There are many cores. Single-thread speed, and PHP and Magento work one thread at a time, is from another era.
The tools are lscpu and vmstat, not the CPU chart in the vendor panel.
Why this measurement
You run it before purchase, before renewal, and when the store is slow at “40 percent CPU” in the panel. A slower core lengthens cart response time no matter how many vCPU are in the offer. Missing hardware AES loads TLS and disk encryption. The st column in vmstat means neighbours on the same host take the time slice. 32 GB in the offer is not always 32 GB for your machine only.
How to check
On a fresh VPS with SSH: lscpu. Record the CPU model, the CPU count, whether the aes flag is there, and the clock. Then vmstat 1 30 in the store traffic hour, not at night. Average st above several, ten percent usually rules the host out for Magento.
In the application look at the cart and a filtered listing, not the homepage behind a CDN. The vendor benchmark runs on an empty host. Your indexer and cron measure reality.
Four vCPU on a newer EPYC or Xeon Gold often beat sixteen vCPU on an old E5. In a public cloud the CPU family is in the instance name. On your own Proxmox you see host CPU in the panel. If the vendor will not name the model, measure it yourself or change host.
Environment choice: cloud and on-prem.
In short: the vCPU count in the offer does not describe store performance. Before you renew, check the CPU model and whether the hypervisor gives the machine time.