Amazon RDS now supports R5b instances for MySQL and PostgreSQL databases

Amazon Relational Database Service (Amazon RDS) now supports R5b database (DB) instances for MySQL and PostgreSQL databases. R5b DB instances support up to 3x the I/O operations per second (IOPS) and 3x the bandwidth on Amazon Elastic Block Store (Amazon EBS) compared to the latest x86-based memory-optimized DB instances (R5) available in Amazon RDS for MySQL and PostgreSQL databases. R5b DB instances are a great choice for IO-intensive DB workloads.

Source:: Amazon AWS