Which generation is that server? Dell, HPE, Lenovo, Cisco and Supermicro side by side.

Five counting systems

Dell counts in G — 13G, 14G, 15G — and puts the count inside the model number: the letter is the form factor, the first digit the class and the second digit the generation, so R730, R740, R750 and R760 are thirteenth to sixteenth generation. A four-digit name follows the same rule with the socket count and the processor maker added — R7515 is fifteenth generation, one socket, AMD. HPE puts it in a suffix, DL380 Gen9, Gen10, Gen10 Plus. Lenovo ThinkSystem adds a version suffix to an unchanged model number, and the suffix is the part of the name that dates it. Cisco UCS uses an M suffix, C240 M4 to M8. Supermicro dates a machine by its motherboard, X10 to X13 on Intel, so on an older Supermicro the board model is the line to read.

None of these numbers line up with each other — Gen10 is not the same age as 10G, and M6 is not the sixth of anything you can compare. What they share is the processor platform underneath, because every two-socket Intel server of a given era is built around the same processor family and the same memory generation. The table lines them up on that axis.

The same platform under five names

Each entry links to that generation on its line page, where the processor, memory and storage ceilings are listed with the specification sheets they were read from. A dash is a generation we have not verified against the vendor's own document, left empty rather than filled in from memory. The Dell entry in the Xeon 6 row is the 1U R670; the other entries in that row are 2U machines.

Why the platform is the comparison that matters

Within one row of the table, the machines are close relatives. They take the same processors, the same type of memory at broadly the same speed, and they arrived with the same generation of PCIe. The differences between two vendors in one row are about management tools, drive cages, controllers and support — real differences, but not the ones that decide how fast the workload runs.

Between rows, the differences are the ones that do decide it: cores per socket, memory speed and ceiling, and whether front NVMe bays exist at all. That is why a quote for a Dell R740 and a quote for an HPE DL380 Gen10 can be compared directly, and a quote for an R740 against a DL380 Gen11 cannot — the second sits two rows further down, so the two quotes are for different machines.

Each cell in the table links to the generation on its line page, where the processor, memory and storage ceilings are listed with the specification sheet they were read from.

Dating a listing that does not say which generation it is

Plenty of listings give a model and nothing else. Four things settle the generation quickly:

• The processor model. The family name on the listing — E5-2600 v3, a 2nd Gen Xeon Scalable part, a Xeon 6 — places the machine in one row of the table, whatever the chassis is called.
• The memory type. DDR3 means the oldest row; DDR5 means the 4th Gen Scalable row or newer. Everything in between is DDR4.
• The management controller. iDRAC8 is Dell 13G and iDRAC9 arrived with 14G; on HPE, iLO 5 covers both Gen10 and Gen10 Plus, and iLO 6 arrived with Gen11. The controller narrows the generation down; the model name on the same management page settles it.
• The drive bays. EDSFF bays such as E3.S belong to the newest platforms in the table; a machine with them is not a refurbished bargain from three generations back, whatever it is priced at.

What the generation means for the decision

Older is a set of ceilings, not a verdict on quality: slower memory, fewer cores per socket, fewer or no fast drive bays. If the workload never reaches those ceilings — file and print, directory services, backup storage, most mixed virtualisation — the older row is the cheaper way to buy the same result. If it does reach them — an all-flash database, GPU inference, high-speed networking — the newer platform is what you are paying for, and no amount of RAM in an older chassis buys it back.

Two cases override that trade. Adding to machines already in the rack means matching the vendor and the generation rather than the exact model: within one vendor's generation, memory, drive carriers and controllers are shared across models, while across vendors even the drive carriers differ. And a virtualisation cluster that has to move running machines between hosts is easiest to grow in the generation it already runs; mixing generations is possible, but the hypervisor has to be set up for it, so ask before pricing a newer host into an older cluster.

For a refurbished purchase, the next questions are about the individual machine rather than its generation — what to check before you buy refurbished covers them. For the chassis height, 1U, 2U or tower covers the physical side of the same choice.