Use the AWS Instance Utilization dashboard to identify which EC2 instances have a high usage across the metrics for CPU, Disk IO, Network Transmissions, Received/Sent, and Memory. Use that information to determine whether you can optimize the system by adjusting the EC2 instances.
For example, you might determine that you need to resize the EC2 instance to make it larger or smaller.
You most often use this dashboard to troubleshoot issues with the listed metrics based on a support request from a user.
You can also identify which EC2 instances have been running for the longest and shortest amount of time. Then, you can use that information to determine whether EC2 instances can be decommissioned, or discover instances that have been added and need to be tracked in inventory.
Memory metrics require that you implement an add-on for each EC2 instance. These add-ons cost extra, and are not included by default.