The Same DIMM Has Two Part Numbers, and the Wrong One Costs You a Delivery

Written and maintained by Haink's infrastructure team · Verified against HPE ProLiant QuickSpecs and HPE support documentation, 29 August 2026 · authorized-channel, serial-verified before payment

HPE part numbers look like a single opaque string and are actually four decisions stacked on top of each other: which component, which region it is warranted in, whether it is installed at the factory or by you, and whether the number you are holding is the one you order or the one printed on the part.

Get any of those wrong and the consequence is not a rounding error. A memory kit ordered under the wrong suffix arrives loose in a box instead of installed in the server. A part with a European suffix delivered to Dubai carries a warranty that does not follow it. And a factory-only option cannot be added later at any price — the order has to be placed again.

The suffix is geography

The trailing block after the dash is the region the SKU is sold and warranted in. From HPE's own QuickSpecs:

This matters most in exactly the markets our customers operate in. A quote full of -421 parts is an EMEA quote; if the hardware is landing in Hong Kong or Singapore, ask why. Regional SKUs are one of the standard routes by which gray-market stock reaches a buyer — the price is attractive because the warranty is registered somewhere else. The wider version of that problem is in gray-market channel risks.

Put the suffix in the requirement. "All part numbers to be the SKU warranted for the country of installation, stated on the quote" is one line and it closes the whole issue.

CTO, FIO and field options are three different things

HPE separates how a machine can be built, and the rules are stricter than most buyers assume:

• CTO base model. A configure-to-order chassis onto which processors, memory and options are selected — for example P52534-B21, an 8SFF NC CTO server. QuickSpecs is explicit: "Factory Integrated Models must start with a CTO Server."
• Factory Integrated Option (FIO). "FIO indicates that this option is only available as a factory installable option." If it is not on the original order, it cannot be added later. This is the one that catches projects.
• Field option. Installable after delivery — but note the reverse restriction: "Hewlett Packard Enterprise does not allow factory integration of options into pre-configured models." A pre-configured server cannot be sent back to the factory to have things added.

The practical consequence for a project: the specification has to be complete before the order, not after. On a forty-node build, discovering a FIO requirement in week three does not mean adding a line item — it means re-placing the order and taking the lead time again. This is why the sequence in buying twenty to sixty servers as one project puts specification before quoting rather than after.

The memory trap: -B21 and -F21 are the same DIMM

This one is stated plainly in QuickSpecs and almost never repeated by anyone selling the hardware:

"The -B21 memory SKUs shown in this document are to be used when ordering stand-alone memory only. For each -B21 SKU, there is a corresponding -F21 SKU which is to be used when configuring servers with integrated memory DIMMs."

So the same physical module has two order numbers. -B21 is the module on its own, in a box. -F21 is the module configured into a server at the factory. Order -B21 when you meant -F21 and the memory arrives correctly — and uninstalled, on a pallet, next to forty servers that someone now has to open.

On a single machine that is an afternoon. On a project it is a scheduling failure, and it is entirely avoidable by asking one question of the quote: are the memory SKUs the integrated ones?

The number on the part is not the number you order

HPE maintains two identities for the same component: the option part number, which is what appears on a quote and in QuickSpecs, and the spare part number, which is what is physically labelled on the component and what service uses. They are different strings for the same thing.

Which produces two failure modes worth knowing:

1. Quoting from a label. Someone reads a number off a drive or a DIMM in a running server and asks for more of them. That number is the spare, and ordering against it is not the same transaction as ordering the option.
2. Verifying a delivery. The number on the arriving part will not match the number on the purchase order, which looks like an error and is not.

HPE publishes a Spare/Option Parts Lookup that translates between them. Use it before raising a discrepancy, and use it before quoting from anything you read off a physical machine.

What to require on an HPE quote

1. Full part number for every line, including the suffix — not a product description.
2. Regional suffix matching the country of installation, stated explicitly.
3. Memory SKUs confirmed as integrated where the servers are to arrive built.
4. Every FIO identified, with confirmation that it is on the original order, because it cannot be added afterwards.
5. Serial numbers supplied before payment for stock units, for warranty and entitlement verification — the same discipline described in verifying an in-stock offer.
6. Warranty term and support entitlement stated separately from the hardware line, for the installation country rather than the country of purchase.

Frequently asked questions

What does -B21 mean on an HPE part number?

It is the regional suffix, and -B21 is the worldwide SKU. Other regions have their own: -421 for Europe, the Middle East and Africa, -291 for Japan, -AA1 for China and -D61 for India. The suffix determines where the part is sold and warranted.

Can we buy a -421 part for a server in Asia?

It will physically work, but it is warranted for a different region, and regional SKUs sold outside their market are one of the standard routes gray-market stock reaches buyers. Require the suffix to match the country of installation and have it stated on the quote.

Why does the same memory have two part numbers?

Because HPE distinguishes standalone memory from memory configured into a server at the factory. QuickSpecs states that -B21 memory SKUs are for ordering stand-alone memory only, and that each has a corresponding -F21 SKU for configuring servers with integrated DIMMs. Order the wrong one and the memory arrives in a box rather than in the server.

What is a FIO and why does it matter?

A Factory Integrated Option. HPE states that a FIO is only available as a factory installable option, which means it cannot be added after delivery. On a multi-node project, discovering a FIO requirement after the order is placed means re-ordering and taking the lead time again — so the specification has to be complete before the order, not during it.

Can HPE add options to a pre-configured server at the factory?

No. HPE does not allow factory integration of options into pre-configured models, and factory integrated models must start from a CTO server. If you need a factory-built configuration, the order has to start from the configure-to-order base.

Why doesn't the number on the part match our purchase order?

Because HPE maintains two identities: the option part number you order against, and the spare part number physically labelled on the component. They differ for the same item. HPE publishes a Spare/Option Parts Lookup that translates between them — check there before raising a discrepancy.

Can we quote from a number read off a running server?

Not directly. That number is almost certainly the spare part number, which is not what you order against. Translate it to the option part number first, or you will be quoting a different transaction from the one you intend.

Related

• How to choose HPE ProLiant servers and storage — workload-to-model selection and host sizing
• HPE four-socket scale-up — DL580 Gen12 against two DL380, and why 4U buys only memory
• HPE support tiers explained — why four-hour response is weaker than six-hour repair
• HPE iLO and Compute Ops Management licensing — the remote console is a per-server licence
• HPE memory population rules — why 12 DIMMs per processor runs at half the bandwidth of 8
• HPE Alletra explained — what happened to 3PAR, Primera and Nimble, and the lifecycle dates
• HPE DL360 vs DL380 Gen12 — 1U or 2U, and why memory is not the reason
• HPE ProLiant Gen11 vs Gen12 — the core-variant and memory-speed decision
• GreenLake vs owning the hardware — what the consumption contract actually charges for
• Sourcing HPE — the routes hardware reaches you by, and how to tell which one a quote came through
• Gray-market channel risks — how regional SKUs reach the wrong market
• Verifying an in-stock offer — what to confirm before payment
• Buying 20–60 servers as one project — why the specification has to be complete before the order
• Lenovo MTM and part numbers — the equivalent scheme on the other platform, for mixed estates
• Dell PowerEdge vs HPE ProLiant · the three-way comparison
• HPE stock, lead times and pricing · stock vs BTO/CTO

Sources

• HPE — ProLiant DL380 Gen11 QuickSpecs (regional suffixes -B21, -421, -291, -AA1 and -D61; CTO base models; "Factory Integrated Models must start with a CTO Server"; the FIO definition; the -B21 and -F21 memory SKU distinction)
• HPE — ProLiant DL360 Gen11 QuickSpecs (the same conventions on the 1U platform)
• HPE Support — Spare/Option Parts Lookup (translating between option and spare part numbers)