Question 206 of 1,040
Design Cost-Optimized ArchitecturesmediumMultiple ChoiceObjective-mapped

SAA-C03 Design Cost-Optimized Architectures Practice Question

This SAA-C03 practice question tests your understanding of design cost-optimized architectures. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A team runs an EC2-based API on a single Auto Scaling group (ASG). Over the last month, they observed: - Average CPU utilization is ~15%. - p95 latency is stable and within the performance target. - The attached EBS volumes are gp3, provisioned with high baseline IOPS/throughput “just to be safe,” but CloudWatch shows consistently low utilization of those provisioned IOPS/throughput limits. They want to reduce monthly cost while maintaining current performance. Which action is the best cost-optimized choice?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "best"

    Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

Question 1mediummultiple choice
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Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Right-size both the compute and the gp3 volumes: reduce the EC2 instance size (via the ASG launch template/desired capacity configuration) and update gp3 IOPS/throughput settings to match observed utilization while keeping p95 latency targets.

Option B is correct because the workload is over-provisioned in both compute and storage. Average CPU is only 15%, so a smaller instance size can handle the load without affecting p95 latency. The gp3 volumes have high baseline IOPS/throughput that are never used, so reducing them to match actual utilization directly lowers costs without performance risk.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Stop resizing EBS and only scale out the ASG during peak traffic, because changing EBS performance settings risks latency spikes.

    Why it's wrong here

    The problem includes both overprovisioned gp3 performance and underutilized CPU. Only scaling out during peaks increases compute cost and does not address the consistently low gp3 IOPS/throughput utilization that is already wasting money.

  • Right-size both the compute and the gp3 volumes: reduce the EC2 instance size (via the ASG launch template/desired capacity configuration) and update gp3 IOPS/throughput settings to match observed utilization while keeping p95 latency targets.

    Why this is correct

    The metrics indicate headroom that is not being used (low CPU, stable latency, and low gp3 utilization). The most direct cost optimization is to reduce overprovisioned spend by right-sizing the instance type and tuning gp3 IOPS/throughput to match actual demand. Because performance and latency are already stable, these changes are the most likely to reduce cost without degrading performance.

    Clue confirmation

    The clue word "best" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Switch the instances to EC2 Spot immediately, because Spot always lowers costs without adding operational risk or affecting performance.

    Why it's wrong here

    Spot can reduce costs, but it introduces possible interruptions and capacity variability. The prompt does not state the workload can safely handle interruptions, and it does not guarantee that performance will remain stable under Spot interruptions/replacements.

  • Move the workload to a larger instance class and keep the gp3 settings unchanged to avoid operational tuning work.

    Why it's wrong here

    Using larger instances increases compute cost and does not address the unnecessary gp3 provisioned IOPS/throughput that is already underutilized. This contradicts the goal of reducing cost while maintaining performance.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates assume EBS performance settings are fixed or risky to change, or that scaling out the ASG is always the best cost optimization, when in fact gp3 allows flexible, no-downtime IOPS/throughput adjustments and the real savings come from matching provisioned resources to actual utilization.

Detailed technical explanation

How to think about this question

gp3 volumes have a baseline of 3,000 IOPS and 125 MB/s throughput for any size, with additional IOPS/throughput provisioned and billed separately. CloudWatch metrics like VolumeReadOps and VolumeWriteOps show actual usage, and you can modify gp3 IOPS/throughput without downtime or performance impact as long as you stay above the baseline. Right-sizing EC2 instances involves analyzing CloudWatch CPUUtilization and network metrics to select a smaller instance type (e.g., from m5.large to t3.medium) that still meets the p95 latency target, often using a launch template update and adjusting ASG min/max/desired.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this SAA-C03 question test?

Design Cost-Optimized Architectures — This question tests Design Cost-Optimized Architectures — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Right-size both the compute and the gp3 volumes: reduce the EC2 instance size (via the ASG launch template/desired capacity configuration) and update gp3 IOPS/throughput settings to match observed utilization while keeping p95 latency targets. — Option B is correct because the workload is over-provisioned in both compute and storage. Average CPU is only 15%, so a smaller instance size can handle the load without affecting p95 latency. The gp3 volumes have high baseline IOPS/throughput that are never used, so reducing them to match actual utilization directly lowers costs without performance risk.

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

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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This SAA-C03 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAA-C03 exam.