According to the documentation: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html
The page size of Mysql is twice bigger than the postgresql one:
MySQL/Maria, 16 KB Pages, 30,000 max IOPS
PostgreSQL, 8 KB Pages, 30,000 max IOPS
This is a problem because the max data block considered a single IOPS is 32kb in RDS. so if you are asking for 30,000 pages pf MySQL data you may reach a 480Mb/s throughput vs 240Mb/s in Postgres for exactly the same amount of money.
Is this really how RDS works? is MySQL twice as good in disk access cost according to the AWS pricing?