Extended Power Capacity is specifically designed to increase usable power in a Cisco UCS X-Series chassis while the chassis remains configured in a redundant power mode. Cisco states that enabling Extended Power Capacity permits the chassis to borrow power capacity from the supplies reserved for redundancy, thereby increasing the total power that can be allocated to workloads.
Cisco provides a six-PSU example in Grid redundancy mode. Without Extended Power Capacity, the workload is capped at 8,400 W. Enabling the feature increases the available workload capacity to approximately 9,660 W—an increase of 15 percent—while retaining the configured redundant power mode.
Power capping in option A would restrict consumption rather than make additional power available. Adding more PSUs is impossible when the chassis already contains its supported complement of six supplies. Disabling Extended Power Capacity would reduce rather than increase the available power envelope.
This feature is particularly useful after installing additional accelerator, PCIe, memory, or compute resources that raise chassis power demand. It should nevertheless be applied within the data center's electrical and thermal design limits.
Study Guide Reference: AI Infrastructure Operations and Troubleshooting — UCS X-Series chassis power policy, redundancy, Extended Power Capacity, and capacity management.
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