IBM Power 11 CPU

The processor feature code is the real unit of a Power 11 purchase. Every published option, what each one benchmarks at, and how the choice moves the IBM i software tier.

You do not buy a Power 11. You buy a processor feature code, and everything else follows from it: the core count, the clock, the CPW, the rPerf, the software tier, and the maximum size of any single partition you can build. Two S1124 machines sitting in the same rack can differ by a full software tier because of which module went in the socket, and that difference recurs on every license renewal for the life of the system.

This page lists every published Power 11 processor option with its benchmark figures, so the feature code decision can be made against numbers rather than model names.

Power 11 processor packaging

eSCMOne chip per module, 4 to 20 cores, 3.05 to 4.0 GHz
DCMTwo chips per module, 16 to 60 cores, 2.4 to 4.4 GHz
Cache per core2 MB L2, 8 MB L3
ThreadingUp to SMT8

The entry single-chip module appears only on the S1112 and S1122. Everything above that is dual-chip. The trade is consistent across the whole line: the highest-core features run the lowest base clocks, so a 60-core module is a consolidation machine and a 4-core module is a response-time machine.

Scale-out processor features: S1112, S1122, S1124

ModelFeatureCoresClock (GHz)ModuleCPWIBM i tier
S1112EJMT43.6 ... 4.0eSCM117,300P05
S1112EJSV103.05 ... 4.0eSCM116,500P10
S1122ERGR4 or 83.6 ... 4.0eSCM118,200 / 236,400P10
S1122ERGQ10 or 203.05 ... 4.0eSCM124,500 / 123,400P10
S1122EBG816 or 323.0 ... 4.2DCM124,500 / 123,800P10
S1122EBG924 or 482.65 ... 4.15DCM124,500 / 123,800P10
S1122EBGA30 or 602.4 ... 3.95DCM124,500 / 117,100P10
S1124EP3X16 or 323.4 ... 4.2DCM433,000 / 823,000P20
S1124EP3H24 or 483.05 ... 4.15DCM649,800 / 1,118,500P30
S1124EP3Y30 or 602.8 ... 3.95DCM812,250 / 1,345,900P30

Where two core counts share a feature code, they are the single-socket and dual-socket builds of the same module, and the CPW figures pair with them in that order.

The S1124 is the clearest tier trap in the family. EP3X keeps the machine at P20. Stepping up to EP3H or EP3Y for more cores also steps the entire system into P30, and that applies to IBM i, the licensed program products, and most third-party IBM i software for as long as you own the box. Price both before you settle the configuration.

Linux-focused processor features: L1122, L1124

ModelFeatureCoresClock (GHz)Positioning
L1122ERGF16 or 323.0 ... 4.2P10 tier, Linux-first
L1122ERGG24 or 482.65 ... 4.15P10 tier, Linux-first
L1122ERGH30 or 602.4 ... 3.95P10 tier, Linux-first
L1124EP4C16 or 323.4 ... 4.2IBM i and AIX capped at 25% of activated cores
L1124EP4B24 or 483.05 ... 4.15IBM i and AIX capped at 25% of activated cores
L1124EP4J30 or 602.8 ... 3.95IBM i and AIX capped at 25% of activated cores

The L-series carries the same silicon at the same core counts as its S-series sibling. What differs is the licensing posture, not the processor. If IBM i is more than a quarter of the workload, the L1124 is the wrong machine no matter how attractive the hardware price looks.

Enterprise processor features: E1150, E1180

ModelFeatureCoresClock (GHz)Benchmark
E1150EPEX16 per socket, to 643.5 ... 4.2rPerf 2,285 at 64 cores
E1150EPEY24 per socket, to 963.3 ... 4.2rPerf 3,698 at 96 cores
E1150EPEZ30 per socket, to 1203.0 ... 4.1rPerf 4,571 at 120 cores
E1180EDQ040 to 803.9 ... 4.2CPW 1,049,100 / 2,098,300
E1180EDQ948 to 963.9 ... 4.4CPW 1,290,000 / 2,580,100
E1180EDQD64 to 2563.8 ... 4.3CPW 1,572,800 / 3,145,600

The E1150 does not support IBM i at all, which is why it carries rPerf rather than CPW. It is an AIX and Linux machine. The E1180 is the only Power 11 system that reaches 256 cores, across a four-node sixteen-socket build, and the EDQ9 feature carries the highest clock in the entire Power 11 line at 4.4 GHz.

Reading the benchmark numbers correctly

CPW and rPerf answer different questions and are not interchangeable. CPW measures commercial transaction throughput and is the figure that reads across IBM i generations. rPerf measures relative AIX performance and is published at each SMT level, which is why the same processor shows four different rPerf figures.

The SMT spread is the part buyers skip. On the S1112 EJSV feature, single-thread rPerf is 95.4 and SMT8 rPerf is 298.7. That is roughly a three-fold difference from the same silicon depending on how the workload threads. A batch job that cannot parallelize sees the first number, not the last one.

Full CPW and rPerf explanation

How to confirm the CPU in a system you already run

WhereWhat to runWhat it gives you
IBM iDSPSYSVAL QPRCFEATThe processor feature code directly ... the one value worth writing down
IBM iWRKHDWRSC *PRCProcessor resources visible to the partition
AIX, Linux, VIOSlsconf, prtconfProcessor type, implementation and clock speed
AIX, Linux, VIOSlparstat -iEntitled and online capacity for this partition
HMCManaged system properties, processor tabInstalled cores against activated cores ... the only view that separates them

Installed cores, activated cores and licensed cores are three different numbers, and quotes are inconsistent about which one they mean. Capacity planning uses activated cores. Software licensing usually follows activated cores. Upgrade headroom follows installed cores. Get all three in writing before you sign anything.

Next steps

Per-model detail, including the full per-feature CPW and rPerf tables, is on each system's directory entry: S1112, S1122, S1124, L1122, L1124, E1150 and E1180.

For the licensing consequence of a feature code, see IBM i licensing and OS compatibility on Power 11. For the wider configuration around the processor, see the Power 11 specs page, and for what it costs, Power 11 pricing. If you are replacing an entry-tier machine, the S1112 against every prior P05 system is the comparison that matters.

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