EC2 T-Instance CPU Credits Depleted: Sustained Baseline Throttling Before Resizing

<h2>Symptom</h2> <p>When an Amazon EC2 T2, T3, or T4g instance shows CPUCreditBalance near zero during peak hours while CPUUtilization stays at the instance baseline, the goal is to determine whether the workload is being throttled to baseline CPU performance because credits are exhausted, and whether that pattern justifies resizing to a fixed-performance instance class or adjusting the workload instead.</p> <p>Constraints: a single low credit sample is not conclusive because diurnal load patterns can temporarily drain credits. T3 Unlimited may bill for surplus CPU instead of throttling, masking the symptom as higher cost rather than reduced performance. Credit balances are instance-specific and do not transfer across stops or size changes.</p> <ul> <li>Does a multi-day downward trend in CPUCreditBalance confirm sustained baseline throttling rather than intermittent bursting?</li> <li>Should the instance be resized to a fixed-performance class, or should the workload be changed to stay within the T-instance baseline?</li> <li>What difference does T3 Unlimited surplus-credit billing make compared with standard mode?</li> </ul>