SAA-C03 Design Cost-Optimized Architectures Practice Question

A company has a steady-state workload running on Amazon EC2 instances that must run 24/7 for the next 3 years. The workload uses a consistent instance family and size across multiple Availability Zones. The company wants to achieve the maximum possible discount and is willing to make an upfront payment. Which purchasing option should a solutions architect recommend?

⚠ Common exam trap

The trap here is assuming that Convertible Reserved Instances or Savings Plans always give the best discount, when in fact Standard RIs offer the highest discount for fixed, predictable workloads.

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

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Standard Reserved Instances (3-year, All Upfront)

Standard Reserved Instances provide the largest discount for steady-state workloads with a known instance family and size, especially with a 3-year All Upfront payment. They also offer a capacity reservation within an Availability Zone. Convertible RIs and Compute Savings Plans offer flexibility at the cost of a lower discount. On-Demand is the most expensive. Thus, Standard RIs meet the requirement for maximum discount.

Answer analysis

Option-by-option breakdown

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

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On-Demand Instances
Why it's wrong here
On-Demand Instances provide flexibility without upfront commitment, but they are the most expensive option for long-term, steady-state workloads. The company is willing to commit for 3 years and make an upfront payment, so they can achieve significant savings with Reserved Instances or Savings Plans. On-Demand does not offer any discount and would result in higher costs over the 3-year period.
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Convertible Reserved Instances (3-year, All Upfront)
Why it's wrong here
Convertible Reserved Instances offer the ability to change instance attributes during the term, but they provide a lower discount compared to Standard Reserved Instances. Since the workload uses a consistent instance family and size, there is no need for the flexibility of Convertible RIs. The maximum discount is achieved with Standard RIs, not Convertible, so this option leaves money on the table.
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Compute Savings Plans (3-year, All Upfront)
Why it's wrong here
Compute Savings Plans offer discounts and apply to a wide range of compute services and instance families, but their discount rate is typically lower than that of Standard Reserved Instances for a specific instance family. Since the workload is fixed and predictable, Standard RIs yield a greater discount. Compute Savings Plans are better when flexibility across families or regions is needed, but here the goal is maximum discount for a known configuration.
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Standard Reserved Instances (3-year, All Upfront)
Why this is correct
Standard Reserved Instances offer the highest discount among Reserved Instance types, especially with a 3-year All Upfront commitment. Because the workload is steady, uses a consistent instance family and size, and runs across multiple AZs, Standard RIs are a perfect fit. They provide a capacity reservation and significant cost savings compared to On-Demand, and the All Upfront payment maximizes the discount.

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SAA-C03 Design Cost-Optimized Architectures Practice Question

Why each option matters

Option-by-option breakdown

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