Power 9 Power Requirements
IBM Power 9 and AS400 power requirements by machine type: rated voltage, maximum power draw in watts, thermal output in BTU per hour, weight and rack units for every Power 9 model, plus IBM's own measured idle and maximum figures.
Most Power 9 power questions get answered with a generation-wide guess, and the guess is always wrong, because an S914 and a four-node E980 are not the same electrical problem. This page gives the actual published figures per machine type: what IBM rates each model at, what IBM measured each model drawing, and how far apart those two numbers are. Start from the machine type on the bezel, not the generation name.
Power 9 power requirements by machine type
IBM published electrical and physical ratings, Power 9 family
| Machine type | Model | Operating voltage | Max power | Max thermal | Weight | EIA |
|---|---|---|---|---|---|---|
| 5105-22E | S922 entry | 200 - 240 V ac | 800 W | 2,730 BTU/hr | 30.4 kg | 2U |
| 9009-41A | S914 | 100 - 127 or 200 - 240 V ac | 1,600 W | 5,461 BTU/hr | 36.3 kg | 4U |
| 9009-41G | S914 | 100 - 127 or 200 - 240 V ac | 1,600 W | 5,461 BTU/hr | 36.3 kg | 4U |
| 9009-22A | S922 | 200 - 240 V ac | 1,880 W | 6,416 BTU/hr | 30.4 kg | 2U |
| 9009-22G | S922 | 200 - 240 V ac | 1,880 W | 6,416 BTU/hr | 30.4 kg | 2U |
| 9008-22L | L922 | 200 - 240 V ac | 1,880 W | 6,416 BTU/hr | 30.4 kg | 2U |
| 9223-22H | H922 | 200 - 240 V ac | 1,880 W | 6,416 BTU/hr | 30.4 kg | 2U |
| 9223-22S | H922S | 200 - 240 V ac | 1,880 W | 6,416 BTU/hr | 30.4 kg | 2U |
| 9009-42A | S924 | 200 - 240 V ac | 2,750 W | 9,386 BTU/hr | 39.9 kg | 4U |
| 9009-42G | S924 | 200 - 240 V ac | 2,750 W | 9,386 BTU/hr | 39.9 kg | 4U |
| 9223-42H | H924 | 200 - 240 V ac | 2,750 W | 9,386 BTU/hr | 39.9 kg | 4U |
| 9223-42S | H924S | 200 - 240 V ac | 2,750 W | 9,386 BTU/hr | 39.9 kg | 4U |
| 9040-MR9 | E950 | 200 - 240 V ac | 4,220 W | 14,403 BTU/hr | 69 kg | 4U |
| 9080-M9S | E980 | 200 - 208 / 220 - 240 V ac | 4,130 W per node | 14,095 BTU/hr per node | 86.2 kg per node | 5U per node |
All models are single phase at 50 or 60 Hz plus or minus 3 Hz. Figures are IBM's published maximum ratings from the Power 9 server specifications documentation. The E980 line is per system node: a four-node E980 is four times these numbers plus a 2U system control unit, which is why a fully populated E980 needs its own electrical plan rather than a rack-level assumption.
The S914 is the only Power 9 that will run on a 120 V circuit. Every other machine type in the family requires 200 - 240 V ac. If a room was built around single-phase 120 V and the replacement machine is an S922 or S924, the electrical work is the project, not the server.
What a Power 9 actually draws
The ratings above are what the machine is permitted to pull. They are not what it pulls. IBM files measured figures for these same machine types in its EU ecodesign technical documentation, testing a high-end and a low-end configuration of each. Those measurements are far below the rating, and the gap is the difference between a correctly sized room and an expensively over-built one.
IBM measured idle and maximum power, Power 9 machine types
| Machine type | Model | Sockets | Measured idle | Measured maximum | Rated maximum |
|---|---|---|---|---|---|
| 9009-41A | S914 | 1 | 163.4 ... 200.3 W | 239.1 ... 350.5 W | 1,600 W |
| 9009-22G | S922 | 1 | 182.4 ... 216.4 W | 254.9 ... 463.4 W | 1,880 W |
| 9009-22G | S922 | 2 | 251.1 ... 321.4 W | 389.8 ... 823.2 W | 1,880 W |
| 9008-22L | L922 | 2 | 292.7 ... 340.0 W | 657.1 ... 685.9 W | 1,880 W |
| 9223-22S | H922S | 1 | 182.4 ... 216.4 W | 254.9 ... 463.4 W | 1,880 W |
| 9223-22S | H922S | 2 | 251.1 ... 321.4 W | 389.8 ... 832.2 W | 1,880 W |
| 9009-42A | S924 | 1 | 205.0 ... 233.5 W | 480.9 ... 567.8 W | 2,750 W |
| 9009-42A | S924 | 2 | 280.6 ... 339.2 W | 886.9 ... 964.9 W | 2,750 W |
| 9223-42H | H924 | 1 | 205.0 ... 233.5 W | 480.9 ... 567.8 W | 2,750 W |
| 9223-42H | H924 | 2 | 280.6 ... 339.2 W | 886.9 ... 964.9 W | 2,750 W |
| 9223-42S | H924S | 1 | 254.6 ... 280.6 W | 580.4 ... 685.7 W | 2,750 W |
| 9223-42S | H924S | 2 | 325.4 ... 379.3 W | 965.4 ... 1,199.4 W | 2,750 W |
| 9040-MR9 | E950 | 2 | 513.9 ... 820.8 W | 1,059.5 ... 1,271.9 W | 4,220 W |
| 9040-MR9 | E950 | 3 | 666.1 ... 1,126.5 W | 1,528.1 ... 1,788.9 W | 4,220 W |
| 9040-MR9 | E950 | 4 | 855.6 ... 1,445.8 W | 2,025.2 ... 2,339.5 W | 4,220 W |
Each range runs from IBM's tested low-end configuration to its tested high-end configuration. Source: IBM Technical Documentation for EU Regulation 2019/424, published per machine type. All Power 9 entries are declared operating condition class A2. Machine types absent from this table are ones IBM has not filed a cleanly readable measurement for, not ones that draw nothing.
Read the S924 row carefully. A two-socket 9009-42A measured at just under 965 W flat out, against a 2,750 W rating. Sizing the circuit, the UPS and the cooling to 2,750 W buys roughly three times the capacity the machine will ever ask for. Sizing to the measured 965 W with no margin is the opposite mistake. The useful number sits between them, and it depends on which configuration you actually own.
Sizing the circuit from these numbers
Start from the rating, not the measurement
Electrical codes and inspectors work from nameplate ratings. A 9009-42A at 2,750 W on a 208 V single-phase feed draws about 13.2 A, so a 20 A circuit at the usual 80 percent continuous-load derating gives 16 A of headroom. The measurement tells you what the room will feel; the rating tells you what the circuit has to be.
Size the UPS from the measurement
UPS runtime is where the measured figure earns its keep. Sizing a battery to the 2,750 W rating when the machine draws 965 W buys runtime you already had. Size to measured maximum plus a real margin, then test the batteries, because a UPS that was correct at install has lost capacity every year since.
Cooling follows thermal output
One ton of cooling removes roughly 12,000 BTU/hr. A single S924 at its 9,386 BTU/hr rating is most of a ton on its own. Four of them in a rack is a three-ton problem before storage, network, or the HMC are counted.
Redundant supplies do not double the draw
Two power supplies in a Power 9 share the load and exist so either can carry it alone. They do not double consumption. They do mean two feeds, ideally from separate circuits, which is a distribution question rather than a capacity one.
How to read actual draw from a machine you already run
From the HMC
Managed system properties reports the installed power supplies and their status. The HMC is also the only place that separates installed cores from activated cores, and activated cores are what drives real consumption on a Power 9 with capacity upgrade on demand.
From IBM i
DSPSYSVAL QPRCFEAT returns the processor feature code. That code, not the model name, is what determines where in the measured range your machine actually sits. WRKHDWRSC *PRC lists what the partition can see.
From the PDU
A metered or switched rack PDU gives the only number that is truly yours: measured amps on the outlet feeding the machine, under your workload, with your adapters and drives installed. Everything on this page is a starting point for that measurement.
From the label
The machine type and model on the bezel is enough to pick the right row of the ratings table. It is not enough to place you in the measured range, because that depends on processor feature, memory count, and installed adapters.
What to confirm before you migrate, relocate, or extend
1. Confirm your exact model
An S914 and an E980 were never close to the same electrical load, weight, or footprint, and that gap matters even more now that both are past new sale. Start from the specific machine type installed, not the generation name.
2. Check power supply condition, not just spec
A Power 9 power supply that was correctly sized on day one can still be years into its service life. Confirm current condition and any redundancy loss, not just the original rated capacity.
3. Check UPS battery age, not just runtime rating
A UPS sized correctly at install time loses real runtime as its batteries age. If the UPS has not been tested or the batteries have not been replaced in years, the effective runtime today is not the nameplate number.
4. Re-verify the room, not just the machine
Rooms drift over years of service: added equipment, blocked airflow, and shared circuits all change the picture. Re-verify circuits and cooling capacity against what is actually installed in the room today, not what was planned when the Power 9 first arrived.
5. Weigh facilities risk into the keep-or-migrate decision
An aging power feed is a real input into whether to extend a Power 9 with third-party maintenance or move to Power 10 or Power 11, not a separate problem to solve later.
6. Check the replacement before you assume it needs more
It usually needs less. A Power 11 S1124 is rated at 2,950 W against the S924's 2,750 W, but does vastly more work inside that envelope, and an S1112 is rated at 550 W. Moving forward a generation is frequently a reduction in facilities load, not an increase.
Choose the install target
Basic install
Keep the current Power 9 running safely with correct circuit capacity, rack fit, PDU load, UPS capacity, and a clean shutdown procedure.
Sustainable install
Add UPS battery testing, measured load, monitoring, labeled feeds, cooling margin, and documented failover or shutdown steps before extending the system.
Growth install
Reserve rack, PDU, circuit, UPS, cooling, and cable headroom if this room may support a Power 10, Power 11, storage, network, or HA move next.
Sources for every figure on this page: IBM's Power 9 server specifications for the ratings, and IBM's EU Regulation 2019/424 technical documentation for the measured figures, filed per machine type.
Confirm which machine type you are planning around on the Power 9 models page, and check the processor feature against the Power 9 CPU reference, because the processor feature is what places a machine in the measured range above. If the real question is whether to keep running Power 9 at all, start with Is Power 9 End of Life? and Power 9 End of Support Dates. For the facilities-readiness walkthrough that spans every generation including AS/400 and iSeries-era systems, see AS400System.com's Power server power requirements guide. If you need a reseller or facilities partner, use BigTechReseller's AS400 power requirements partner page.