Amazon developed its own ARM core for its own cloud services

Today we are launching EC2 instances powered by Arm-based AWS Graviton Processors. Built around Arm cores and making extensive use of custom-built silicon, the A1 instances are optimized for performance and cost. They are a great fit for scale-out workloads where you can share the load across a group of smaller instances. This includes containerized microservices, web servers, development environments, and caching fleets.

Interesting to see Amazon design its own ARM core specifically for its own product.