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What Does My RAM Part Number Mean?

Portrait of Devin ChuaBy Devin Chua · Data checked by Owen Nakamura · Updated
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FieldValueConfidence
MakerKingstonConsistent across the models we checked
LineServer PremierConsistent across the models we checked
GenerationDDR4Consistent across the models we checked
Speed3200 MT/sConsistent across the models we checked
Module typeRegistered DIMM (RDIMM)Consistent across the models we checked
Error correctionECCConsistent across the models we checked
Capacity16 GBConsistent across the models we checked
OrganisationDual rank, x8Consistent across the models we checked
In short

Paste a memory part number to read back its generation, module type, error correction and, where the vendor encodes it, capacity and organisation. We read Kingston, Samsung, SK hynix, Micron, Dell and HPE. Several vendors use pure SKUs that encode nothing, and we say so rather than inventing a reading.

The formula

Kingston   KSM + speed + module type + organisation / capacity
           KSM32RD8/16HDR = 3200 MT/s, Registered ECC, dual rank x8, 16 GB

Samsung    first four characters give generation and module type (M393 = DDR4 RDIMM)
SK hynix   HMA/HMAA = DDR4, HMCG = DDR5; R/U/S = RDIMM/UDIMM/SODIMM
Micron     MTA = DDR4, MTC = DDR5; 72 = ECC data path, 64 = non-ECC
Dell       SNP<code>/<capacity>G  (capacity after the slash)
HPE        P00000-B21 is an order SKU and encodes nothing

Worked examples

Each example is the function this page runs, with the inputs shown. A test asserts these results still match the code.
CaseInputsWorkingResult
Kingston serverKSM32RD8/16HDR32 -> 3200 MT/s, R = registered ECC, D8 = dual rank x8DDR4-3200 ECC RDIMM, 16 GB, 2Rx8
SamsungM393A4K40DB3-CWEM393 = DDR4 RDIMM; density block not publishedDDR4 ECC RDIMM, capacity unknown
HPE SKUP00924-B21no structure to readNot in our decoder yet

Why this tool exists now

Crucial's Advisor configurator was for years the default answer to "what memory fits my machine", and it effectively disappeared in early 2026 alongside Micron's exit from the Crucial consumer brand. Nothing has replaced it. That removed the most widely used compatibility tool in the market at exactly the moment when buying the wrong module became expensive.

This decoder does not replace a compatibility list, and it is important to be clear about that. It reads what a part number encodes, which tells you what a module is. Whether that module works in your board is a separate question that depends on the platform.

What each vendor actually encodes

Kingston's Server Premier line is the most readable: speed, module type, organisation and capacity all appear in a consistent structure, so KSM32RD8/16HDR decodes cleanly to a 3200 MT/s registered ECC module, dual rank by eight, 16 GB. Samsung, SK hynix and Micron encode generation and module type reliably but bury density in schemes they have never published a general key for, so we decode what is documented and leave the rest.

Dell states capacity after the slash in its SNP numbers and encodes the rest as a SKU. HPE's B21 numbers encode nothing whatsoever: they are pure order codes, and the only route to their specification is the QuickSpecs document for that server generation. Saying so is more useful than inventing a reading.

Module types are not interchangeable

A registered DIMM buffers the address and command lines, which is what lets a server populate more modules per channel without signal integrity collapsing. An unbuffered DIMM does not, and is what desktops use. A load-reduced DIMM buffers the data lines too, for the highest capacities. A board takes one type, and putting the wrong one in will not work regardless of capacity and speed matching. Checking the type before buying is the single most useful thing this decoder does.

Questions

Why will it not tell me the capacity of my Samsung module?

Samsung encodes density and organisation in the characters after the prefix but has never published a general key for them. We decode the generation and module type, which are reliable, and leave the rest to the label rather than guess.

Why does an HPE part number decode to nothing?

Because HPE B21 numbers are order SKUs with no structure at all. There is no rule to apply, only a lookup, so the honest answer is to point you at the QuickSpecs for your server generation.

What is the difference between RDIMM, UDIMM and LRDIMM?

A registered DIMM buffers the address and command lines, which lets a server populate more modules per channel. An unbuffered DIMM does not and is what desktops use. A load-reduced DIMM buffers the data lines too, for the highest capacities. They are not interchangeable: a board takes one type.

Does ECC in the part number mean my board will use it?

No. The module having ECC and the platform enabling it are separate questions, and on consumer boards the answer to the second is often no. Our ECC support check covers that.

Can I mix part numbers in one system?

Within a channel, matching rank and organisation matters more than matching part numbers. Mixing speeds makes every module run at the slowest one. Servers are stricter: most OEM matrices require identical modules within a bank, and some require identical groups of eight.

Sources