Do you have some numbers? According to here [1] an i3.16xlarge will get you "up to to 3.3 million random IOPS at a 4 KB block size and up to 16 GB/second of disk throughput. "

What does Oracle claim? I see here they say 1 million IOPS.[2]

[1] https://aws.amazon.com/blogs/aws/ec2-instance-type-update-t2...

[2] http://www.biwasummit.org/biwa/wp-content/uploads/2016/12/84...