SOA-C02 Cost and Performance Optimization Practice Question
A company runs a critical application on a fleet of EC2 instances that process real-time financial transactions. The application requires consistent low latency. The SysOps administrator notices that the application's latency increases periodically due to noisy neighbors. The administrator wants to optimize performance predictability. Which instance type should the administrator choose?
⚠ Common exam trap
SOA-C02 often tests the distinction between tenancy (Dedicated Instances/Hosts) and pricing models (Reserved/Spot) — candidates incorrectly pick Reserved Instances thinking the discount implies isolation, when only dedicated tenancy removes noisy neighbors.
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
✓
Dedicated Instances
Dedicated Instances run on hardware dedicated to a single customer, eliminating the noisy-neighbor problem because no other AWS accounts share the underlying physical host. This provides the performance predictability required for consistent low-latency financial transaction processing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Burstable Performance Instances (T3)
Why it's wrong here
T3 instances rely on CPU credits to handle bursts of activity, but when the credit balance is exhausted, CPU performance is hard-limited to the baseline rate, which can cause severe throttling for a critical application requiring sustained CPU. Because your workload uses a fleet of instances with consistent high utilization, burstable instances will frequently run out of credits, leading to unpredictable latency and degraded throughput. This makes T3 instances unsuitable for production workloads that demand steady, dependable compute performance.
- ✓
Dedicated Instances
Why this is correct
Dedicated Instances run on hardware that is physically isolated from other AWS accounts, meaning there are no 'noisy neighbors' that can monopolize CPU, memory, or I/O resources. This single-tenant environment provides strong performance consistency and can also satisfy strict compliance or licensing requirements. For a critical application running on a fleet, this isolation ensures that the behavior of other customers cannot interfere with your instances, making it the correct choice.
- ✗
Spot Instances
Why it's wrong here
Spot Instances offer large cost savings by letting AWS reclaim the capacity at any time with a brief two-minute warning when AWS needs it back for on-demand or reserved workloads. This interruption risk means a Spot Instance can be terminated mid-transaction, causing application crashes or data loss, which is unacceptable for a critical application. While Spot is economical for fault-tolerant or flexible workloads, it does not provide the reliability needed for a mission-critical service.
- ✗
Reserved Instances
Why it's wrong here
Reserved Instances are primarily a billing discount applied to your accounts, not a reservation of physical capacity or a guarantee of performance isolation. Your instances still share underlying hosts with other customers, so the 'noisy neighbor' effect remains possible and can degrade performance. Choosing RI will save on usage costs, but it does nothing to mitigate contention or provide the dedicated hardware that this critical workload requires.
Go deeper
Related to this question
About these practice questions
One of 1,169 original SOA-C02 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
This SOA-C02 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 SOA-C02 exam.