SAA-C03 Design Cost-Optimized Architectures Practice Question
A marketing site runs on x86 EC2 instances and uses open-source software with no architecture-specific licensing restriction. What should be evaluated to reduce compute cost? The architecture review board prefers a managed AWS-native control.
⚠ Common exam trap
Test-takers frequently assume Dedicated Hosts (Option D) are cost-effective for all workloads, but they actually increase costs due to per-host billing and are only justified for specific licensing or compliance needs, not general compute cost reduction.
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
✓
AWS Graviton-based instances after performance testing
AWS Graviton-based instances use ARM-based custom processors that offer up to 40% better price-performance compared to comparable x86 instances for many workloads. Since the marketing site runs open-source software with no architecture-specific licensing restrictions, migrating to Graviton after performance testing can significantly reduce compute costs while leveraging a managed AWS-native control (e.g., EC2 Auto Scaling groups with Graviton instance types).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Cross-Region data replication for all data
Why it's wrong here
Cross-Region data replication stores duplicate data in a second AWS Region, incurring costs for inter-region data transfer, the replicated storage itself, and additional infrastructure to keep copies in sync. For a marketing site with no explicit disaster-recovery or data-residency requirement, this replication is an operational safety net, not a cost-optimization strategy, and it substantially increases the monthly bill without improving runtime performance.
- ✗
io2 Block Express volumes for all instances
Why it's wrong here
io2 Block Express is an EBS volume designed for high-availability, high-throughput enterprise databases with up to 256K IOPS and sub-millisecond latency, and its per-GB price is significantly higher than gp3 or standard volumes. A marketing site, typically a web front-end with modest I/O, would pay a premium for performance headroom it rarely uses; choosing this for all instances is an extravagant over-provisioning rather than a cost-saving measure.
- ✓
AWS Graviton-based instances after performance testing
Why this is correct
AWS Graviton instances run on custom Arm-based processors and, for many workloads, deliver up to 40% better price performance than comparable x86 instances, especially for web servers running open-source software that is already compiled for ARM. The recommended approach is to performance-test the application on Graviton first—because it's a different architecture and some native libraries must be recompiled—then use instance types like m7g or t4g for production, which can cut compute cost without sacrificing throughput.
- ✗
Dedicated Hosts by default
Why it's wrong here
Dedicated Hosts are physical servers dedicated to a single customer, typically used to meet server-bound software licensing constraints or compliance rules, and they are billed per host, which is almost always more expensive than running the same instances on shared hardware. Choosing Dedicated Hosts by default not only forfeits the lower cost of default shared tenancy but also locks you into paying for the entire host even when it is underutilized, making it an anti-pattern for pure cost reduction.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.