Amazon ElastiCache for Redis is designed to be an in-memory data store that supports sub-millisecond latency, which is essential for real-time applications such as gaming leaderboards. It offers high performance with the flexibility to scale up or down to meet fluctuating demands. Amazon DynamoDB Accelerator (DAX) is specific to Amazon DynamoDB and is optimized for read-heavy and bursty workloads. Amazon Aurora is a relational database that, although performant, does not offer the in-memory capabilities of ElastiCache. Amazon RDS provides managed relational databases but also lacks the in-memory data handling optimized for the described use case.