AWS Certified Solutions Architect Associate Test 6

In AWS, the instance size decides the I/O characteristics. The provisioned IOPS ensures higherthroughput, and lower latency. The region does affect the latency; latency will always be less whenthe instance is near to the end user. Within a region the user uses any AZ and this does not affect thelatency.
The AZ is mainly for fault toleration or HA.
Reference: http://media.amazonwebservices.com/AWS_Security_Best_Practices.pdf