CloudWatch metrics show your EC2 instances have average CPU utilization around 10% with stable performance over several weeks. The application does not require additional headroom right now. What is the most effective cost-optimization action?

Increase the Auto Scaling desired capacity to add more instances

Adding more instances increases total compute capacity and typically increases cost, even if CPU utilization is low. Auto Scaling is intended to respond to demand changes; raising desired capacity without a demand need does not address the current overprovisioning.

Switch to Spot Instances immediately even though interruptions would impact users

Switching to Spot is a pricing decision that introduces interruption risk. The scenario’s primary measurable issue is persistent underutilization; switching to Spot would be unnecessary and potentially risky given the stated interruption impact. Cost optimization here should first target the dominant cost lever: oversized compute.

Disable detailed monitoring to reduce CPU usage from the monitoring agent

Reducing monitoring detail might lower monitoring charges, but it does not address the main driver of EC2 cost: unused instance capacity. Any CPU impact from monitoring is usually minor compared with the savings from downsizing instances.

What does this SAA-C03 question test?

Read the scenario before looking for a memorised answer.

What is the correct answer to this question?

The correct answer is: Right-size the instances to a smaller size that matches the observed utilization — Right sizing is the most direct cost-optimization step because persistent low utilization indicates the instances are larger than required. When average CPU is around 10% for weeks and the application remains stable, downsizing reduces the hourly compute cost while keeping performance within acceptable limits for normal fluctuations. The other options increase capacity cost (higher desired capacity), introduce operational risk unrelated to the metric evidence (Spot interruptions), or optimize a smaller secondary cost (monitoring) without fixing the overprovisioned compute spend. Why others are wrong: Increasing Auto Scaling desired capacity increases spend despite low CPU utilization. Spot is a separate decision that trades lower price for interruption risk and does not inherently solve overprovisioning. Disabling detailed monitoring reduces some monitoring costs, but it does not meaningfully address the dominant EC2 cost created by oversized instances.

What should I do if I get this SAA-C03 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.