Explanation
Why the waste happens and who it affects.
If real-world usage plateaus below provisioned levels, a portion of the PTU capacity remains idle but still generates full spend each hour. This is especially common shortly after production launch or during adoption of newly released model versions, where early conservative sizing leads to long-term over-allocation. Rightsizing PTUs based on observed usage patterns ensures that capacity matches actual demand.
Billing model
The pricing dimensions that drive this cost.
PTU pricing is based on the number of provisioned throughput units, not actual usage. Underutilized PTUs still incur full hourly charges, making over-allocation a direct source of avoidable cost.
How to detect
4 checks to find it in your estate.
- Review PTU deployments for consistently low or flat throughput utilization over representative time periods
- Compare provisioned PTU levels against actual workload demand to identify idle capacity
- Identify deployments sized for initial peak estimates that no longer match steady-state usage
- Evaluate whether recent model or workload changes have altered throughput requirements
How to fix
4 ways to remove the waste.
- Reduce PTU allocations to align with actual utilization while preserving required performance levels. If the PTUs are covered by a reservation, pair the scale-down with a reservation exchange or cancellation (fees and limits apply), otherwise the reservation keeps billing its original quantity and there are no savings; released capacity may also not be available again later
- Implement recurring rightsizing reviews to adjust PTU levels as workload patterns evolve
- Use workload performance testing to validate that reduced capacity meets latency and throughput goals
- Consider shifting variable or declining workloads from PTUs to PAYG where appropriate
Documentation
Vendor references for pricing and configuration.