The detail about all AWS EC2 instances types can be found here: https://aws.amazon.com/ec2/instance-types/

“General Purpose”

• General Purpose come with two family which is the first character in the name:
  • “M”: general, fixed CPU performance.
  • “T”: burstable performance with baseline level of CPU
• The second character is instance generation, the newest generation got the biggest number
• The next character is Processor family:
  • “i”: Intel CPU
  • “a”: AMD CPU
  • “g”: AWS Graviton CPU
• And there are some additional information:
  • “flex”: Flex instance, usually better price / performance with lower prices compare to the same instance type without “flex”
  • “n”: Network and EBS optimized
  • “z”: High performance

“Compute optimized”

Following the same naming convention as General Purpose:

• “C”: Compute optimized

“Memory Optimized”

Following the same naming convention as General Purpose:

• Family:
  • “R”: Memory optimized
  • “U”: High memory
  • “X”: Memory intensive
• And there are some additional information:
  • “b”: Block storage optimization
  • “d”: Instance store volumes
  • “e”: Extra storage or memory

And so on…. 🙂