An IBM i administrator at a mid-sized distribution company gets a simple question from the board: “what do we buy to replace the server whose support is running out?”. The first instinct is to open the catalogue and pick the model with the highest core count the budget allows. The second, slower one is to count how many cores actually work under load today and which licence tier the system sits in. The second answer usually points to a smaller server than the catalogue suggests.
The Power11 generation makes shortcuts harder, because the model names suggest differences that do not exist and hide the ones that do. In this guide we narrow the choice in the order an experienced architect would: licensing, memory, installation site, availability requirements. Every parameter comes from IBM product pages, the Power11 launch announcement or IBM Redbooks. We do not repeat the comparison with the x86 architecture — we cover it in a separate article on x86 and RISC physical servers.
Which IBM Power servers are on offer today, and how does Power11 differ from Power10?
The current family consists of five Power11 servers and one cloud service. The IBM Power family page lists the S1112, S1122, S1124, E1150 and E1180, plus IBM Power Virtual Server. IBM announced Power11 on 8 July 2025 and set general availability for 25 July 2025. For the first time in the platform’s history, a launch covered entry, mid-range and high-end servers and their IBM Cloud version at the same time.
IBM’s Redbook on the E1180 (SG24-8587, September 2025) describes the Power11 processor as an evolution of the Power10 chip used in the E1080. The changes concern 7 nm technology, higher core density, DDR5 memory bandwidth and reliability mechanisms. For a buyer, however, the platform features IBM stresses most matter more: maintenance without planned downtime, IBM Power Cyber Vault and quantum-safe cryptography.
Some Power10 models still live in IBM’s documentation and on its pages. The S1012 is a Power10 server that ibm.com describes as the edge server of the portfolio. The L1022 is a Power10 model outside the current offering. The L1122, by contrast, is a current Power11 model, even though IBM keeps no separate product page for it — it appears in technical documentation (machine type 9856-22H). Its larger 4U counterpart, the L1124 (9856-42H), is described the same way.
It is also worth not confusing Power with LinuxONE. LinuxONE belongs to the IBM Z family, which we write about in the article on IBM LinuxONE servers. It has a different architecture, different operating systems and a different licensing model.
Power11 in one paragraph: five servers (S1112, S1122, S1124, E1150, E1180), the Linux variants L1122 and L1124 in the documentation, and Power Virtual Server in the cloud. AIX, IBM i and Linux run on a single PowerVM hypervisor. The largest model takes up to 256 cores and 64 TB of DDR5 memory.
Where should you start: cores, memory or licences?
With licences. In IBM i environments, AIX with Oracle or Db2, and SAP systems, the cost of software licensed per core or per tier can exceed the cost of the hardware over the full life cycle. A server with spare cores “for the future” can push the system into a more expensive tier on day one.
IBM’s documentation shows this with concrete thresholds. The S1112 supports IBM i in the P05 tier, i.e. up to 4 cores and 64 GB of memory. An S1122 with at most 16 cores fits in the P20 tier, while 48- and 60-core configurations fall into P30 (Redbook SG24-8590, October 2025). The same model, two different licences.
The second parameter is memory, because it most often forces a larger chassis. The third is the installation site: a full server room, a rack in a branch office or the cloud. Core count comes last, and IBM provides tools so that you do not have to buy it up front. Capacity on Demand lets you activate cores as needed. Power Enterprise Pools 2.0 lets you share them between servers.
The practical advice from migration projects is simple. Before discussing a model, collect three numbers from the current system: actual peak core utilisation, memory use and the current licence tier. Without them, every quote is guesswork, including the one from the vendor.
When is the smallest server enough: S1112 or S1012?
When the workload is small and the licence should stay in the lowest tier. In the Power11 generation the smallest model is the S1112. IBM describes it as an entry-level server for modernising AIX, IBM i and Linux workloads in branch offices, retail locations, manufacturing sites and banks. It is available as a 2U rack server or as a deskside machine.
The S1112 takes up to 512 GB of DDR5 memory and up to 12.8 TB of local NVMe drives. IBM does not state its maximum core count on the product page. It does give a performance comparison: an S1112 core is 2 times faster than in the Power S914 and 3 times faster than in the Power S814. This is a CPW result for 4-core configurations, valid as of 14 July 2026 according to IBM’s footnotes. For the owner of an old S814, it means the same work will fit on fewer cores.
The S1012 is a half-wide Power10 server, available as a 2U rack or tower model. It has 1, 4 or 8 cores and up to 256 GB of memory. The 1-core option is for IBM i only, and the 8-core option is available only in the rack version. Each core runs four Matrix Math Accelerators.
IBM does not call the S1112 the successor of the S1012, and neither do we. They are two different generations with different limits. For a new purchase, Power11 is the reference point, and the S1012 makes sense mainly where compatibility with an existing Power10 fleet or a very small configuration matters.
How do the S1122, L1122 and S1124 really differ?
Not in core count. The S1122 and the S1124 share the same ceiling — up to 60 Power11 cores. They differ in memory (4 TB versus 8 TB), chassis (2U versus 4U), the number of NVMe drives (up to 8 versus up to 16) and room for cards. You therefore choose the S1124 when you run short of memory or slots, not compute.
The S1122 also has the widest configuration range in the family. It starts with two 4-core processors and ends with two 30-core ones. The same model can therefore serve a single IBM i system in the P20 tier or a consolidation of a dozen or more partitions. The S1122 can also join existing Power Enterprise Pools 2.0 with Power10 S1022 and S1024 servers, which makes a staged migration easier.
The L1122 is a variant of the S1122 for the Linux segment. According to Redbook SG24-8590, at least 75% of activated cores must run Linux partitions. Up to 25% can be used for AIX or IBM i, for example for a single database next to a Linux farm. The L1122 uses only 16-, 24- and 30-core modules per processor, so the smallest configuration has 32 cores.
If the environment is predominantly Linux, the L1122 is the natural candidate. If IBM i or AIX dominates, the right starting point is the S1122. If memory runs short in either case, you have to move up to the S1124.
When do you need an E1150, and when only an E1180?
The E1150 fills the gap between scale-out servers and a full rack. It is a 4U server with 2, 3 or 4 sockets, each holding a 16-, 24- or 30-core module — up to 120 cores and 16 TB of DDR5 memory in total. A two- or three-socket system can later be expanded to four sockets, and each socket has two spare cores.
The E1150 is usually bought to consolidate several critical systems on a single machine. Going beyond 8 TB of memory or 60 cores in a single system is a signal that the S1124 is no longer enough. Redbook SG24-8589 (October 2025) also lists support for cryptographic modules certified to FIPS 140-3 and resource sharing in Power Enterprise Pools 2.0.
The E1180 is the flagship full-rack server: up to four nodes, up to 16 sockets, up to 256 Power11 cores and 64 TB of DDR5 memory. IBM aims it at the biggest, most complex critical workloads. It also describes an upgrade path from Power10 that keeps the machine’s serial number, which matters when carrying licences over.
The boundary between them rarely comes from performance. What decides is the memory scale, the number of systems to consolidate and whether the organisation needs a server that grows by nodes within a single machine.
What do “99.9999%” and “zero planned downtime” mean on IBM’s terms?
Both figures are true, but they come with footnotes that change their meaning. In its 8 July 2025 announcement, IBM states 99.9999% availability for Power11. In a footnote it specifies that the figure is based on “unplanned downtime of a single Power E1180 system” as calculated by IBM’s RAS analysis. It is not a parameter of the S1122, nor a contractual commitment.
Zero planned downtime, in turn, is a method rather than a feature of a single machine. Redbook SG24-8596 (February 2026) describes it as automated updates working together with Live Partition Mobility, Live Kernel Update and Live Library Update. IBM’s product page adds that some activities — certain firmware updates and hardware service — require moving partitions to another server.
The conclusion for the buyer: maintenance without downtime assumes there is a second system the partitions can move to. A single server, however good, cannot keep that promise on its own. If the requirement reads “zero planned downtime”, the design must include at least two systems or a site in Power Virtual Server.
IBM’s caveats on availability figures: 99.9999% — unplanned downtime of a single E1180, IBM RAS calculation. Ransomware detection by Cyber Vault in under a minute — the guarantee covers the display of an alert. Zero planned downtime — some work requires moving partitions to a second server.
How do IBM i, AIX and Linux affect the choice of model?
The operating system sets both the list of models and the cost of licences. IBM i runs only on Power and is licensed by tier, so the P05, P20 and P30 thresholds matter most for it. They decide whether an S1112 is enough or whether you need an S1122 in a small configuration.
IBM calls AIX a “strategic, foundational component” of its portfolio and says its roadmap and support plan run beyond 2035. AIX environments with Oracle or Db2 usually land on an S1122 or S1124, and in large consolidations on an E1150. Here, the choice of cores translates directly into database licences.
Linux on Power is primarily Red Hat, including OpenShift, which IBM lists among the platform’s workloads. For Linux farms, the candidate is the L1122, with its rule of at least 75% of cores for Linux. In a mixed environment where Linux sits next to a larger IBM i, the S1122 is more convenient.
PowerVM lets you run all three systems on one server in separate partitions. This is an advantage, but also a security decision. Whoever has access to the HMC and the management console has access to all partitions at once.
Can Power Virtual Server replace a server in your own server room?
Sometimes, but it usually complements it. IBM Power Virtual Server offers multi-tenant virtual Power servers in IBM Cloud, billed pay-as-you-go. Since the Power11 launch, IBM has also offered servers of that generation in it.
IBM points to three main uses. The first is backup and a standby site in warm DR mode. The second is development and test environments for the duration of a project. The third is SAP: IBM states that PowerVS holds hyperscaler-platform certification for RISE with SAP, and IBM describes a like-for-like migration from on-premises Power.
For a company choosing a model, PowerVS has one more advantage. It lets you run a workload on Power11 and measure it before the hardware purchase decision is made. The choice of cores then rests on a measurement rather than an estimate.
A standby site in the cloud needs the same protection as production, because it holds production data. We design such sites and run failover tests as part of business continuity planning (BCP/DRP).
Which Power11 security features matter against ransomware?
Three, and each answers a different question. IBM Power Cyber Vault creates immutable, air-gapped copies of data and is integrated with IBM Storage. IBM guarantees attack detection in under a minute with a caveat: the guarantee covers the display of an alert, and the compensation is limited to replacing drives, capped at the value of the covered product.
The second is quantum-safe cryptography: secure boot, a cryptographic inventory and hardware-based encryption tools, which IBM describes for the E1180 and the S1124. The third is spare cores that take over from a core that starts to fail. This is a reliability mechanism, not attack protection, but it shortens outages.
None of these features replaces a backup strategy. The immutability of copies depends on separating the accounts and the recovery console, as we describe in the article on immutable backup. Power servers also tend to be the longest-unpatched systems in an organisation, because “they work, so nobody touches them”. The AIX and IBM i patch cycle has to be planned just like the rest of the infrastructure.
How do you compare IBM Power models?
The simplest way is to match each model with the situation in which it makes sense and with the signal that you should look elsewhere. The parameters come from IBM product pages and Redbooks SG24-8587, SG24-8589 and SG24-8590.
| Model | Generation and chassis | Cores / memory (max.) | When it makes sense | Signal that it is not the right model |
|---|---|---|---|---|
| S1012 | Power10, half-wide, 2U or tower | 1, 4 or 8 / 256 GB | compatibility with a Power10 fleet, very small configuration | new purchase without fleet constraints |
| S1112 | Power11, 2U or deskside | not stated by IBM / 512 GB | branch office, IBM i in the P05 tier | need for more than 512 GB of memory |
| S1122 | Power11, 2U | 60 / 4 TB | mixed IBM i, AIX and Linux, branch or small server room | short of memory or slots |
| L1122 | Power11, 2U | 60 / per IBM documentation | at least 75% of cores for Linux | IBM i or AIX dominates |
| S1124 | Power11, 4U | 60 / 8 TB | memory-intensive databases, regional data centre | more than 60 cores in one system |
| L1124 | Power11, 4U | 60 / 8 TB | at least 75% of cores for Linux, and the L1122 runs short of memory or drives | IBM i or AIX dominates |
| E1150 | Power11, 4U | 120 / 16 TB | consolidating several critical systems | need for more than 16 TB or growth by nodes |
| E1180 | Power11, full rack | 256 / 64 TB | the largest mission-critical workloads | the workload fits in an E1150 |
| Power Virtual Server | Power servers in IBM Cloud, including Power11 | per profile / per profile | DR, testing before purchase, RISE with SAP | requirement to keep data only in your own server room |
The table does not replace measurement. It does show, however, that the question “how many cores” decides the choice only above 60, and before that memory, the operating system and the installation site decide.
What should you check in a quote before buying a Power server?
Six things worth asking every vendor before comparing prices. First: which IBM i licence tier, or how many database licences, the proposed configuration will land in. Second: how many cores are active from the start and how many can be activated later through Capacity on Demand.
Third: whether the quote includes Power Enterprise Pools 2.0 and whether the new server can share a pool with your existing Power10 machines. Fourth: what zero planned downtime means in this particular project, i.e. where partitions will go during maintenance that requires moving them.
Fifth: whether Cyber Vault is in scope, with which IBM storage, and who is responsible for the restore test. Sixth: what the migration path from the current system looks like and whether anyone has checked operating system and application versions against Power11.
Request-for-quote checklist: licence tier after migration; active and dormant cores; PEP 2.0 with the existing fleet; partition relocation plan for maintenance; Cyber Vault scope and restore test; migration path and version compatibility.
We handle configuration sizing, migration from Power10 and PowerVM setup as part of our IBM Power services, and IBM i environments as part of our IBM i system services. We start by measuring the current workload and licences, and only then talk about the model.
Sources cited in the text: IBM Power product pages (ibm.com, as of September 2026); IBM announcement “IBM Power11 raises the bar for enterprise IT” (8 July 2025); IBM Redbooks SG24-8587 (E1180, September 2025), SG24-8589 (E1150, October 2025), SG24-8590 (Power11 Scale-Out, October 2025), SG24-8596 (Zero Downtime, February 2026); IBM Docs — Power11 machine types.
