A burstable EC2 instance in Standard mode slows down after sustained CPU demand above its baseline.
Check depletion of accumulated CPU credits rather than looking only at CPU utilization.
Which metric is most appropriate?
Check CPUCreditBalance for accumulated credits. Standard mode limits performance toward the baseline after depletion; Unlimited uses surplus credits and can incur additional charges.
Detailed explanation
This measures credits consumed during a period, not the current accumulated balance.
This measures credits consumed during a period, not the current accumulated balance.
This reports health-check failure, not CPU credit balance.
This reports health-check failure, not CPU credit balance.
This measures surplus credits used in Unlimited mode, not the accumulated balance needed for this Standard-mode investigation.
This measures surplus credits used in Unlimited mode, not the accumulated balance needed for this Standard-mode investigation.
This is the accumulated credit balance. A Standard-mode instance cannot sustain above-baseline bursting after depletion.
This is the accumulated credit balance. A Standard-mode instance cannot sustain above-baseline bursting after depletion.
Check official documentation
Compare the following points with the official documentation.
Review Standard and Unlimited credit modes and CPU credit monitoring.
Official references
What to confirm
Distinguish accumulated balance, credit usage, and Unlimited surplus credits.
Key points
- CPUCreditBalance
- CPU credit
- Burstable instance
Notes
- Environment: AWS SOA-C03 exam guide and the linked AWS documentation
- Reviewed against the linked AWS documentation on 2026-10-03.
Foundation review
Balance and usage
CPUCreditBalance measures accumulated credits; CPUCreditUsage measures consumption over a period. After depletion in Standard mode, CPU performance is gradually restricted toward the baseline.
Standard and Unlimited
In Unlimited mode, surplus credits can allow bursting even with a zero accumulated balance. Check the credit mode and surplus-credit charging conditions before inferring a performance limit.