Bad disk throughput on Postgres Aurora?

Hello,

does anyone have insight on Aurora Postgres disk throughput / read throughput? We have been thinking of migrating RDS postgres to Aurora but benchmarking our case produced results that are quite scary. Our use case has some disk usage in a sense that disk read speed never goes under 40megabytes/s during day time and can reach up-to 100megabytes/s.

With initial testing on Aurora Postgres instance size db.r6i.4xlarge, I can only get read throughput of 30megabytes/s maximum and seems to never go above that? Is this truly the case? This will prevent us moving to Aurora. With Postgres in RDS we can easily reach 500 megabytes/s peak throughputs.

Edit: tried running simplest possible query to test throughput (select count(*) from ...) and got 400 megabytes/s. doesn't make any sense.