Every organization has their own unique computing and storage needs. By understanding the nuts and bolts of EC2 pricing, you can pay only for the EC2 instances types that best suit your business scenario.
AWS uses many benchmarks to ensure that ECUs are consistently and predictably measured EC2 CPU capacity, regardless of the underlying hardware. It gives a relative measure of the integer processing power of an AWS EC2 Instance Type. However, prospective AWS customers may be alien to this concept, as tradiotional deployments, like those on VMWare, were always declared with vCPU (Virtual CPU).
Let us have a quick look at the primary difference between the ECU and vCPU pricing :
EC2 provides a wide selection of customizable instance types to fit different use cases. This type classification gives you the flexibility to choose the appropriate mix of resources for your applications.
On the other hand, vCPU compares EC2 Instance sizes as CPU (Clock Speed), the number of CPUs, RAM, Storage, etc.
To understand these differences in a much more granular manner, you can read the complete blog here and see how smart CMPs like Botmetric can assist you in scaling your instance sizes to save money.