Finding the right server part number is essential before buying replacement hardware. A server can use multiple versions of the same component, with differences in speed, revision, connector, or compatibility. This guide explains how to identify server part numbers and verify the correct hardware for Dell, HPE, Lenovo, and Cisco servers.
You order a stick of RAM for your server. It arrives, it looks right, and it doesn’t fit, or it fits, and the server refuses to boot. Sound familiar?
This usually happens when a part is bought by model name alone. One server model can ship with several versions of the same part: different speeds, different revisions, different connectors. The name of the server doesn’t tell you which one is inside yours.
The fix is simple. Learn to find the part number, read it properly, and check it before you pay. This guide walks you through that method for Dell, HPE, Lenovo, and Cisco hardware. Browse our server systems as you go if you want to see how real machines are labelled and listed.
Why Part Numbers Matter: Model vs Part vs Spare/FRU Number
Let’s clear up the words first, because people mix them up all the time.
- Model number: the name of the whole server, like a Dell PowerEdge R740 or an HPE ProLiant DL380 Gen10. It tells you what the machine is, not what’s inside it.
- Part number: the code for one specific component, such as a drive, a memory module, or a power supply.
- Spare or FRU number: the code the vendor uses when the part is sold as a replacement. FRU stands for Field Replaceable Unit. It can be different from the number used when the part was first sold on a new server.
- SKU: a code a seller uses to track a product in their own system. It may or may not match the vendor’s number.
These are not interchangeable. A server model can have dozens of part numbers attached to it, and two parts that look identical can carry different numbers for good reasons: a newer revision, a different firmware, a different connector.
You’ll also run into the difference between an OEM part number vs manufacturer part number. The OEM (say, Dell or HPE) puts its own number on a part. The company that actually built the part, like Samsung or Seagate, has its own number too. Both can appear on one label. When you’re buying, the OEM number is usually the one that matches the vendor’s compatibility documents.
This matters most for refurbished and older hardware. When a server is years past its launch, the exact number is often the only reliable way to find a match. Names get vague, product pages disappear, but the number on the label stays the same.
A good server part number lookup starts with the number on the part itself, not the name of the machine it came out of. If you know what you’re after, our server accessories range is a handy place to compare what’s listed against what you’ve found
Finding Part Numbers on Dell, HPE & Lenovo
Most parts carry a printed label. On drives, it’s on the top or side. On RAM, it’s on the module itself. On power supplies, it’s usually on the side or the back. On the server chassis, look for a pull-out tag at the front, a sticker on the top cover, or one on the back panel.
If a label is faded or missing, don’t guess. Use the server’s serial number or service tag to look up what it shipped with, then match from there.
Dell
Dell servers have a Service Tag, a short code of letters and numbers, printed on the chassis and often on a pull-out tag at the front. Enter it on Dell’s support site, and you’ll see the original configuration. That’s the quickest way to do a Dell PowerEdge service tag lookup and see the parts your server came with.
On the parts themselves, Dell labels often show a Dell part number marked as DP/N. That’s the number to match against Dell’s documents. You may also see a second code on the same label, which is usually the component maker’s own number.
HPE
HPE uses three kinds of numbers, and this is where people get caught out.
- Option part number: the number used to order a part as an upgrade for a server. On ProLiant options, it often ends in something like -B21.
- Spare part number: the number used when the part is a replacement. This is the HPE spare part number, and it often ends in -001.
- SKU: the code for a complete product or bundle.
The same drive can therefore have an option number and a spare number, and both are correct. Neither is a typo. HPE’s own PartSurfer tool let s you search by serial number or part number and shows how the numbers connect, and HPE QuickSpecs list which options a server supports.
Lenovo
Lenovo uses a machine type-model (MTM) for the whole server: a four-digit machine type followed by a model code. You’ll find it on the pull-out tag or the label on the chassis. Enter it, or the serial number, on Lenovo’s support site to see the parts list.
For components, Lenovo uses FRU numbers. A Lenovo FRU part number is the code for the replacement part, and it’s the one to match when you’re buying a swap. Lenovo also uses option part numbers for upgrades, and these can differ from the FRU, so check which one your source is using.
Memory is where a lot of mistakes happen, so if that’s what you’re after, read our guide on how to choose server RAM: DDR4 vs DDR5 for Dell, HPE & Lenovo servers before you order.
Cisco & Other Brands
Cisco keeps things tidy. Each part has a Product ID (PID) and a Version ID (VID), plus a serial number. The PID is the name of the part in Cisco’s system, and the VID shows the hardware revision.
The Cisco UCS part number (PID) is normally printed on the label on the part itself. On a running system, the “show inventory” command lists the PID, VID, and serial number for the installed hardware, which is a big help when the label is hard to reach inside a rack.
The VID matters more than people think. Two parts with the same PID can have different VIDs, and sometimes a newer revision needs a newer software version. If you’re comparing Cisco kit with other vendors, our Cisco vs HP vs Ubiquiti network switches comparison is a useful read.
Other vendors have their own systems. Some use one number, some use two, some hide the useful one in small print. The rule doesn’t change: trust the label on the part in your hand, then check that number against the vendor’s own documents.
Drives, RAM, PSUs & Controller Labels
Each component type puts different information on its label, and knowing how to read it is the fastest way to track down the right server spare parts. Here’s what to look for:
Hard drives and SSDs: You’ll usually see the OEM part number, the maker’s model number, capacity, interface (SAS or SATA), form factor (2.5-inch or 3.5-inch), and sometimes spin speed. Interface is the one to double-check. Not every server bay accepts both. Our guide to SAS vs SATA: which server hard drive should you choose? explains the difference.
RAM: A memory label typically shows capacity, module type, speed, and rank layout, in an industry-standard format such as 32GB 2Rx4 PC4-2933Y-R (a generic example of the label format, not a specific product). That string tells you the memory generation (PC4 is DDR4), the speed, and the type (the R at the end means registered).
Power supplies: Look for wattage, input type, hot-plug design, and the OEM number. A 750W unit and an 800W unit may look the same but be built differently, and your server may need two matching units.
RAID controllers: These carry a model name, cache size, and sometimes a firmware note. Controllers are picky. A card that’s fine in one generation of server may not be supported in the next.
Remember that one label can show two numbers: the OEM’s and the component maker’s. The OEM number is the one that ties the part to your server. The maker’s number helps you identify what it really is. Note both down.
Checking Compatibility After You Find the Number
Finding the number is step one. Now you need a proper server compatibility check. Here’s a simple way to do it.
Identify the server model and generation. A Gen9 and a Gen10 server can look alike but take different parts. Check the chassis label or the system information screen.
Match the part number to the vendor’s compatibility documents. Use the OEM’s own parts lists, QuickSpecs, or support pages. These are the source of truth.
Confirm form factor and interface. Check size, connector type, and slot type. A 3.5-inch drive won’t sit in a 2.5-inch bay without a caddy, and even then it depends on the connector.
Check firmware or revision notes. Some parts need a minimum firmware or BIOS version to work. A newer revision might need an update before it’s recognised.
The mistake to watch for is assuming a similar-looking part with a different number will work. It might. It also might not, and it can be hard to tell until it’s installed. If the number differs, find out why before you buy.
For more help, browse our server miscellaneous range, which covers the smaller parts that often get forgotten during a compatibility check.
New, Refurbished & End-of-Life Parts
Part numbers matter even more once a server gets older. Over time, vendors release revisions, swap one part number for another, and stop making certain parts altogether. You may search for a part number and find it has been replaced by a newer one, or that it’s now listed as discontinued.
That’s where end-of-life (EOL) server parts come in. When a server reaches the end of its support life, its parts can get harder to find new. The good news is that a working supply usually exists on the refurbished market.
Refurbished server parts make sense in a few situations:
- Keeping an older server running without buying a whole new one
- Budget repairs, where a new part costs more than the machine is worth
- Non-critical workloads such as test servers, backups, and labs
Refurbished doesn’t mean guesswork. The same rules apply. Match the number, check the revision, and confirm compatibility.
Compatible parts come in every category. You might pick up a matched RAM module to fill a spare slot, a drive to replace a failing one, a spare power supply for redundancy, a RAID controller to restore an array, or a network adapter to add ports. Match each one by part number, not by name. For more on buying refurbished, our article on refurbished vs new network switches breaks down the value question in detail.
Compatible parts are available in all categories. You could acquire a matched RAM module to install in an unused RAM slot, a drive to plug into an existing drive that is dying, a spare power supply to use in case of a failure, a RAID controller to restore an existing RAID, or a network adapter to install an additional port. Identify each one by part number and not the name. If you’re interested in more information on the value of buying refurbished, read our article on refurbished vs new network switches, which breaks down the value question in detail.
Common Mistakes to Avoid
- Ordering by model name only. The model doesn’t tell you which version of a part is inside.
- Ignoring revisions. A different revision can mean different compatibility.
- Assuming parts are interchangeable. Similar looks and similar specs don’t guarantee a match.
- Copying a number from a photo without checking the label. Photos can be blurry or show a different revision. Read the label on the part in front of you.
Server Part Number Checklist
Keep this handy before every order.
| What to check | Where to find it |
|---|---|
| Server model and generation | Chassis label or OEM system information |
| Component part number | Label on the part itself |
| Spare/FRU number (if different) | OEM label or documentation |
| Revision/version | Label on the part |
| Form factor and interface | Part label and OEM compatibility documentation |
Match the number on the part, not the name of the server.
Conclusion
The right hardware comes from the right number, not from the model name. Once you know where to look, reading a label takes a minute, and it can save you days of returns and downtime.
Find the number, read it, check it against the vendor’s documents, and then buy. If you’d like a second pair of eyes, browse our server accessories or send our team the part number and we’ll help you find compatible hardware.
FAQ
How do I find the part number of a server component?
Check the label on the part itself. If you can’t read it, use the server’s service tag or serial number on the vendor’s support site to see the original parts list.
What is the difference between a model number and a part number?
A model number names the whole server. A part number identifies one specific component inside it. One model can use many different part numbers.
What is an FRU number?
FRU stands for Field Replaceable Unit. It’s the number a vendor uses for a replacement part, and it can differ from the number used when the server was first sold.
Can I use a part with a different part number as a replacement?
Sometimes, but don’t assume so. A different number can mean a different revision, interface, or firmware need. Check the vendor’s compatibility documents first.
Why do OEM part numbers differ from the component maker’s number?
The OEM, such as Dell or HPE, gives the part its own number for tracking and support. The company that built the part has its own separate number. Both can appear on one label.
Is it safe to buy refurbished server parts using the part number?
Yes, as long as you match the exact number, check the revision, and confirm compatibility. Buying from a seller who tests and lists parts by number helps too