Brands we trade
Server Memory Brands: Samsung, SK hynix and Micron
GTR Supply buys and sells server memory by the lot, quoted against the exact module part number, and this page shows you how to read one. It starts with a fact that makes a mixed pallet far less intimidating than it looks: almost all of the memory die used in server modules comes from three companies, Samsung, SK hynix and Micron. Every other name on a memory label is either one of those three under a different brand, or a module house that buys die from them and assembles the module. So a pallet of a dozen brands is usually three families of parts wearing different stickers. Each of the three encodes capacity, rank, organisation and speed into its part number in its own way, and this page decodes all three. Every part number here is identification help for the reader, never a stock listing. Send the part numbers with counts and we will tell you where we stand.
How to identify it
Work out what you have.
Where the identifying number physically sits, how to read each field in it, and what it tells a buyer. Useful whether or not you ever trade anything with us.
Three fabs, many labels, and where Kingston and Crucial sit
Almost all of the DRAM die in server memory comes from Samsung, SK hynix and Micron. That single fact is the most useful thing to know when somebody hands you a mixed pallet, because it means the variety in front of you is mostly branding rather than substance.
Two names cause the most confusion. Crucial is Micron's own retail brand, so a Crucial module is a Micron module with a different label on it. Kingston is a module house rather than a fab: it buys die from the three manufacturers and assembles and tests the modules itself, which is a real manufacturing operation and a genuinely different business from making the die. A Kingston server module is identified by its Kingston part number, not by guessing whose die is under the heat spreader.
Then there are the vendor branded modules. Memory carrying a Dell, HPE, Lenovo or Cisco label is made by one of the three and programmed for that vendor's platform. Some server platforms log a warning against memory that is not the vendor's own part, which does not stop the machine but does change who wants the lot.
Decoding the three part numbers
Samsung server modules start with M and then three digits that give the module type. M393 is a DDR4 registered module, M386 is a DDR4 load reduced module, M321 is a DDR5 registered module and M329 covers the higher density DDR5 registered parts. After the type comes a block encoding the density and organisation, then a dash and a short code that is the speed grade.
SK hynix uses the first four characters for the generation. HMT is DDR3, HMA and HMAA are DDR4, with the extra A marking the higher density parts built on newer die, and HMCG is DDR5. The rest of the string carries the density, organisation and speed in the same way.
Micron uses MTA for DDR4 and MTC for DDR5, and its numbering has one very readable field. A part reading 4G72 is a module that is four gigawords wide by seventy two bits, and because those seventy two bits include the error correction, that is a 32GB module. By the same rule 2G72 is 16GB and 8G72 is 64GB.
Rank and organisation: what 2Rx4 and 2Rx8 actually decide
Somewhere on a server memory label you will find a code like 1Rx8, 2Rx4, 2Rx8 or 4Rx4. It is short, it is easy to skip, and it decides whether a module is useful to a particular board.
The number before the R is the rank count. A rank is a set of memory chips the controller addresses as one unit, so a 2R module has two of them. The number after the x is the width of each memory chip in bits.
Two things follow. First, memory controllers support a limited number of ranks per channel, so what you can install is governed by the total rank count rather than the total capacity, and populating a channel past its rank limit either drops the speed or refuses to run. Second, many server platforms depend on x4 organisation for their more advanced error correction, so a 2Rx4 and a 2Rx8 module of the same capacity are genuinely different products even though the sticker capacity matches.
The largest capacity modules use stacked die and are marked differently again. Record the code exactly as it appears.
What to write down, and what stops a module cold
For a memory list, the part number does almost all the work, and the label carries everything else you need beside it: capacity, module type, speed, and the rank and organisation code.
Four things stop a module working regardless of how well the capacity matches. Registered, load reduced and unbuffered modules are not interchangeable, and a board expecting registered modules will not post with unbuffered ones installed. Error correcting and non correcting modules are not interchangeable either. The generation is absolute, so DDR4 does not go into a DDR5 board and the notch position physically prevents it. And module height matters in 1U and blade chassis, where a very low profile module is required and a standard one will not fit under the lid.
Mixing also has a cost. A channel populated with modules of different speeds runs at the slowest, and a lot with several ranks and organisations mixed together has to be sorted into identical types before any of it is useful, which is exactly why a mixed memory pallet is valued as its parts.
What is in circulation
The families you will meet.
Placing your hardware in the right family does most of the work of describing it. Each note below says what separates that family from the one above it.
Samsung DDR4 registered and load reduced
M393 for registered modules and M386 for load reduced. The volume of what circulates from server decommissions of the last decade.
Samsung DDR5 registered
M321 and the higher density M329 parts. Newer, still moving in smaller quantities, and not interchangeable with anything DDR4.
SK hynix DDR4
HMA numbers, with HMAA marking the higher density parts built on newer die. The same module types as Samsung, in a different numbering scheme.
SK hynix DDR5
HMCG numbers. The generational jump is visible in the prefix, which makes SK hynix the easiest of the three to sort by generation at a glance.
Micron DDR4 and DDR5
MTA for DDR4 and MTC for DDR5. The density field in the number is unusually readable once you know that the seventy two includes the error correction bits.
Crucial
Micron's own retail brand. A Crucial module is a Micron module with a different label, which is worth knowing before you split a pallet into two lines.
Kingston and the module houses
Companies that buy die from the three fabs and build and test modules themselves. Identified by their own part number rather than by whose die is underneath.
Vendor branded memory
Modules carrying a Dell, HPE, Lenovo or Cisco label, made by one of the three and programmed for that platform. The vendor part number is the one on the front of the label.
The same categories, every manufacturer
The families above are this manufacturer's own lines. The category pages carry the wider list, everything that circulates in each category whoever built it, with the part number prefix or physical marker that identifies each one. They are identification help rather than stock lists.
None of this is a stock list
Every model name and part number on this page is identification help for the reader. None of it is a stock listing, and nothing here says that GTR Supply holds a particular item. Send the part number and the quantity you need and we will tell you where we stand.
What it is worth
What decides the number.
Condition is only part of it. These are the things that genuinely move a valuation in this line, and most of them are still in your hands when you write the list.
- The exact part number, since capacity and speed alone do not settle whether a module will work in a given board
- Module type, because registered, load reduced and unbuffered modules serve completely different platforms
- Rank and organisation, since 2Rx4 and 2Rx8 modules of the same capacity are different products to a buyer
- Generation, with DDR4 and DDR5 sitting in very different markets
- One part number in real volume rather than a long tail of single modules
- Whether a lot is already sorted into identical part numbers or arrives as a mixed pallet that has to be sorted first
- Module height, since very low profile parts are required in 1U and blade chassis
- Whether modules are still installed in the nodes they came from, which is accepted just as readily as boxed
- Labels intact and readable, because a module whose part number cannot be read has to be tested to be identified
Both sides of the desk
We supply it, and we buy it.
If you are buying
On the selling side GTR Supply supplies server memory in volume across DDR3, DDR4 and DDR5, in registered, load reduced and unbuffered forms, quoted against the exact part number. Send the part number and the quantity and pricing normally comes back the same business day. If you are working from a board or server model rather than a part number, send that instead and the correct module type, rank and organisation will be confirmed before anything is quoted, because this is the category where a loose specification causes the most expensive mistakes. Matched kits are verified together as a set rather than only as individual modules, since a module can pass in isolation and fail once it is running alongside three others on the same channel. If your deployment needs a specific arrangement, say so at quote stage. Nothing on this page is a stock list.
If you are clearing
On the buying side GTR Supply buys used and surplus server memory in bulk, either still installed in the servers or pulled and boxed. Both are accepted equally and neither is treated as the better way to send it. What genuinely helps is a list by part number with a count against each, because a mixed lot has to be sorted into identical types before any of it is useful and doing that work from a list is faster than doing it on a bench. If reading several hundred labels is not realistic, photograph one label per tray or read the module part numbers out of the management controller while the machines are still running, which reports them for a whole fleet at once. Modules with damaged contacts or a cracked circuit board should be listed separately rather than counted in.
Common questions
Server Memory Brands, answered.
Who actually makes server memory?
Almost all of the DRAM die used in server memory comes from three companies: Samsung, SK hynix and Micron. Every other name on a memory label is either one of those three under a different brand, or a module house that buys die from them and builds the finished module itself.
Two names come up constantly. Crucial is Micron's own retail brand, so a Crucial module is a Micron module with a different sticker. Kingston is the best known of the module houses: it buys die from the three fabs and builds the modules, which is a real manufacturing operation but a different one from making the die.
Memory carrying a Dell, HPE, Lenovo or Cisco label is made by one of the three and programmed for that vendor's platform.
The practical consequence for a seller is reassuring. A pallet that looks like a dozen brands is usually three families of parts wearing different stickers, so list it by part number and let GTR Supply group it.
What does 2Rx4 mean on a memory module?
The number before the R is the rank count and the number after the x is the width of each memory chip in bits. So a 2Rx4 module has two ranks built from four bit wide chips, and a 2Rx8 has two ranks of eight bit wide chips.
It matters for two reasons unrelated to capacity. Memory controllers support a limited number of ranks per channel, so what a board accepts is governed by the total rank count rather than total capacity, and pushing a channel past its rank limit either drops the speed or stops the machine posting. And many server platforms rely on four bit wide organisation for their more advanced error correction, so a 2Rx4 and a 2Rx8 module of the same capacity are genuinely different products.
Record the code exactly as it appears, along with the part number. If GTR Supply has the part number the rank and organisation are settled anyway, but the code is a useful cross check on a mixed pallet.
Should I pull the memory out of the servers before selling it?
You do not have to. GTR Supply buys memory either still installed in the machines or pulled and boxed, and neither is treated as the better way to send it.
Where the whole server is going as well, leaving the modules in is usually simpler for everyone. A complete node is a straightforward thing to value, and stripping it first creates work for you that does not come back in the number, because the parts that come out first are always the ones carrying the value.
Where only the memory is being sold, pulled and boxed is entirely normal. Keep modules of the same part number together rather than mixing them, since a lot has to be sorted into identical types before any of it is useful and a pre sorted lot saves that work.
Either way, handle them by the edges and keep them in trays or antistatic packaging rather than loose in a box. Modules with damaged contacts are worth listing separately.
Guides
Identifying it is half the job. These cover what a buyer actually does with your list once you send it, and what the words on a quote mean before you agree to any of them.
RDIMM vs LRDIMM Server Memory Explained
Why four things have to match before a board will post, and how a mixed memory lot gets sorted into value.
What Is a Hardware Lot Manifest
The document that lets you price a mixed lot line by line instead of guessing at an average.
Grade A vs Grade B Hardware Explained
What a condition grade covers, what it cannot cover, and why the same letter means two different things at two suppliers.
Hardware we hold
Clearing it rather than buying
Trademarks
All product and company names are the trademarks of their respective owners. GTR Supply is an independent trader with no affiliation to, authorization from, or endorsement by any manufacturer named on this page.
Tell us the part number and the quantity.
Buying or selling. Send what you are looking for, or a photograph of what you are holding, and we will tell you where we stand. Pricing and valuations normally come back the same business day.
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