AS400 Learning Center

AS400 Power Requirements

AS400 power requirements can mean either electrical requirements for the hardware or processing capacity requirements for the workload. The exact answer depends on whether you are discussing a legacy AS400 cabinet or a modern IBM Power replacement.

AS400 power requirements is an ambiguous phrase. Some people mean the electrical and facility requirements of the hardware itself. Others mean the amount of processing power a workload needs when moving from a legacy AS400 to a newer IBM Power system. Both are valid questions, but they produce very different answers.

Two Different Meanings of Power Requirements

In infrastructure planning, power requirements can mean voltage, amperage, circuit availability, cooling load, rack space, and power distribution for the physical machine. In upgrade planning, power requirements can mean how much CPU, memory, storage, and IBM i licensing tier a workload needs on the replacement server.

Before anyone gives an answer, make sure the discussion is about facility power, compute power, or both.

Electrical Requirements Depend on the Exact Model

There is no single AS400 electrical requirement because the platform spans decades of hardware formats. Older deskside and cabinet systems, later iSeries and System i machines, and current IBM Power rack servers all differ in plug type, voltage expectations, cooling needs, and physical footprint.

That means relocation, colo planning, or decommissioning work should always start with the exact model and feature configuration. The right source is the machine's hardware documentation or a vendor who can match the serial and model details to the correct facility requirements.

Processing Power Is Usually the Bigger Upgrade Question

For most modernization projects, the more important issue is not wall power ... it is workload sizing. Teams need to understand current utilization, CPW, memory footprint, storage growth, and IBM i software tier before choosing a replacement server.

This is where an old AS400 discussion becomes an IBM Power sizing discussion. Start with IBM Power Sizing Basics if the goal is selecting the right current-generation hardware rather than moving an old system physically.

What to Gather Before an Upgrade or Move

Useful inputs include the current model number, serial number, processor configuration, current IBM i release, storage usage, workload growth expectations, facility circuit details, rack space, and cooling constraints. Without those details, any answer about AS400 power requirements will be too generic to trust.

If the real decision is whether to keep the legacy machine or replace it with a newer platform, What Replaced AS400? is the next page to read.

Frequently Asked Questions

Can one AS400 power requirement answer fit every model?
No. AS400, iSeries, System i, and modern IBM Power hardware cover many different chassis and electrical profiles, so the exact requirement depends on the specific model and configuration.
Do modern IBM Power servers use the same power setup as legacy AS400 hardware?
Not necessarily. Modern IBM Power systems often have very different rack, circuit, cooling, and distribution requirements than older AS400-era hardware.
Is AS400 power requirements really a sizing question?
Often yes. Many buyers use the phrase when they are really asking how much IBM Power capacity their IBM i workload needs on a replacement server.