There are FIVE types of Amazon EC2 instances

General Purpose

Balanced computing, memory, and networking

Suitable for web servers, dev environments, and medium databases

Compute-optimized

High virtual CPUs to memory ratio

Ideal for scientific modeling, batch processing, gaming server

Memory-optimized

Designed for large in-memory processing

Perfect for in-memory databases and real-time big data analytics

Accelerated computing

Uses hardware accelerators like GPUs

Targeted at machine learning, video processing, high performance computing

Storage optimized

High sequential read/write access

Great for distributed file systems and data warehousing