Four Sockets in One Box, or Four Sockets in Two Boxes. The Cores Are Identical.
Written and maintained by Haink's infrastructure team · Verified against Lenovo Press SR850 V4 and SR860 V4 product guides and the large-memory workloads introduction, 29 August 2026 · authorized-channel, MTM and serial verified
Four-socket servers get treated as exotic, priced as mission-critical, and specified without anyone running the comparison that actually decides them. So run it: four sockets in one SR850 V4, against the same four sockets spread over two SR650 V4 nodes.
Cores: identical. DIMM slots: identical. Total memory: identical. Licence bill under per-core pricing: identical. Everything that usually drives a server decision comes out level, which means the decision is made entirely by the four things that do differ — and one of them is the reason this product category exists at all.
The comparison nobody runs
| 1× SR850 V4 (4-socket) | 2× SR650 V4 (2-socket each) | |
|---|---|---|
| Sockets | 4 | 4 |
| Max cores | 344 | 344 |
| DIMM slots | 64 | 64 |
| Max memory, total | 16 TB | 16 TB |
| Billable cores | 344 | 344 |
| Memory addressable by one OS instance | 16 TB | 8 TB |
| Rack units | 2U | 4U |
| PCIe slots | Up to 9, plus 2 dedicated OCP 3.0 | 20, plus 4 OCP |
| Failure domains | 1 | 2 |
| NUMA nodes per instance | 4 | 2 |
SR850 V4 figures from its Lenovo Press product guide; SR650 V4 figures from its own guide, doubled. Both platforms use Intel Xeon 6700-series with up to 86 cores per socket, 16 DIMM slots per processor and DDR5 at 6400 MHz at one DIMM per channel.
The one row that decides it
Memory addressable by a single operating-system instance. Sixteen terabytes in one machine, or two separate eight-terabyte machines — and a database cannot be spread across the second one by wishing.
That is the whole reason four-socket exists. If your largest single workload fits inside 8 TB, two 2-socket nodes give you the same compute, the same memory in total, twice the expansion slots and a second failure domain, and they will generally cost less per core. If it does not fit, no amount of scale-out arithmetic helps, because the constraint is inside one process.
Lenovo positions the SR850 V4 and SR860 V4 explicitly for "SAP HANA and in-memory databases, and for scale-up workloads", and that is exactly the right description: these are machines for problems that refuse to be divided.
The row that surprises people
Rack space runs the opposite way to the intuition. The SR850 V4 puts four sockets in 2U. Two SR650 V4 nodes need 4U for the same four sockets. Where rack space or per-rack power budget is the binding constraint — which it frequently is, as we set out in server refresh and consolidation — the four-socket box is the denser answer, not the more extravagant one.
The row that costs you
Expansion. Nine PCIe slots plus two OCP on the SR850 V4, against twenty PCIe slots plus four OCP across two SR650 V4 nodes. If the design carries storage fabric, separate management networking and anything else per node, scale-out wins that comparison decisively. This is the same trade we describe between 1U and 2U chassis, one level up.
SR850 V4 or SR860 V4
Both are four-socket Xeon 6700-series platforms reaching 16 TB of 6400 MHz DDR5. The difference is chassis, and therefore expansion:
| SR850 V4 | SR860 V4 | |
|---|---|---|
| Form factor | 2U | 4U |
| PCIe slots | Up to 9, plus two dedicated OCP 3.0 | Up to 18 |
| Double-wide accelerators | Up to 2 | Up to 4 |
| Drive bays | Up to 24× 2.5″ or 32× E3.S 1T | Up to 48× 2.5″, or 24× 2.5″ SAS/SATA plus 32× E3.S 1T NVMe |
| Memory | 64 DIMM slots, 16 TB | 16 TB |
SR850 V4 from its product guide; SR860 V4 from the Lenovo Press introduction to both platforms, which quotes up to 18 PCIe slots.
Read it as one decision: the SR850 V4 is the dense answer and the SR860 V4 is the expandable one. Choose the 4U only if the slot count, the drive count or the accelerator count genuinely requires it — you are paying two extra rack units for expansion, and in a power-constrained hall those units may be the scarcer resource.
One configuration note worth knowing: the SR850 V4 has four sockets but can be configured with two processors. That makes it a legitimate route to a large memory ceiling without buying four CPUs on day one — but check what a half-populated four-socket board does to your memory population before assuming it, because the balancing rules still apply per processor.
SAP HANA has its own machine type
The SR850 V4 ships under three base configure-to-order models: 7DJSCTO1WW with three-year base warranty, 7DJTCTO1WW with one year, and 7DJUCTO1WW for SAP HANA configurations with a three-year base warranty.
Two things follow. First, the same warranty trap applies here as everywhere else on the line — 7DJS and 7DJT are the same server with two years of difference between them, which is worth rather more on a machine at this price point. See MTM and part numbers.
Second, a HANA-certified configuration is a distinct machine type, not a general-purpose machine with the right components in it. If the workload requires certification, the machine type on the quote has to be the certified one. And note that Lenovo also certifies HANA on the two-socket line — the SR650 V4 has its own HANA machine type, 7DLN — so certification is not what forces you to four sockets. Database size is.
When four sockets is right, and when it is not
| Situation | Answer |
|---|---|
| A single in-memory database larger than 8 TB | Four-socket — this is the case the category exists for |
| SAP HANA scale-up beyond what a 2-socket node holds | Four-socket, on the certified machine type |
| Rack space or per-rack power is the binding constraint | Four-socket — 2U for four sockets beats 4U for four sockets |
| General virtualization consolidation | Scale out — same cores, twice the slots, two failure domains, cheaper per core |
| The node carries heavy storage and network fabric | Scale out — 20 PCIe slots against 9 |
| Availability target needs N+1 without buying two of everything | Scale out — a single four-socket box is a single failure domain |
| Latency-sensitive workload sensitive to NUMA | Scale out, usually — two NUMA nodes per instance rather than four |
The honest summary: four-socket is not a bigger version of a two-socket server, it is a different product for a specific constraint. Bought for that constraint it is excellent value, because nothing else solves it. Bought as "the serious option" for general virtualization, it costs more per core, gives up half the expansion and concentrates the risk — and the cluster arithmetic in sizing an HCI cluster will usually point elsewhere.
Get scale-up and scale-out priced side by side
Send this and we price it — no questions back:
- The memory footprint of your largest single workload — this one number settles most of it
- Total compute and memory across the estate
- Licence model, and whether SAP HANA certification is required
- Rack power budget per rack
- Destination country and target date
You get firm pricing, availability and delivered lead time within one business day.
No specification yet? Send the largest single workload and the totals. We configure a four-socket option and a scale-out option, price both, and show the licence and failure-domain difference.
Frequently asked questions
When do we actually need a four-socket server?
When a single workload needs more memory than one two-socket node can address. The SR850 V4 reaches 16 TB against 8 TB on a two-socket SR650 V4, and a database cannot be split across two machines to get around that. If your largest single instance fits in 8 TB, scaling out gives you the same cores and memory with twice the expansion and a second failure domain.
Does a four-socket server cost more in licences?
Not per core. Four sockets in one SR850 V4 and four sockets across two SR650 V4 nodes both come to 344 cores at maximum, so per-core licensing is a wash. What differs is the price per core of the processors themselves, which is higher on four-socket-capable parts.
Is a four-socket server bigger in the rack?
Usually smaller, which surprises people. The SR850 V4 fits four sockets into 2U; two SR650 V4 nodes need 4U for the same four sockets. Where rack space or per-rack power is the binding constraint, four-socket is the denser option.
What is the difference between the SR850 V4 and the SR860 V4?
Chassis and expansion. Both are four-socket Xeon 6700-series platforms reaching 16 TB of DDR5 at 6400 MHz. The SR850 V4 is 2U with up to nine PCIe slots plus two dedicated OCP 3.0 slots and two double-wide accelerators. The SR860 V4 is 4U with up to eighteen PCIe slots, four double-wide accelerators and up to 48 drive bays.
Can an SR850 V4 run with only two processors?
Yes. It has four sockets but can be configured with two, which is a route to the larger memory ceiling without buying four processors immediately. Check what a partly populated board does to your memory configuration first, because the balancing rules apply per processor.
Do we need a four-socket server for SAP HANA?
Only if the database is too large for a two-socket node. Lenovo certifies HANA on both: the SR850 V4 has a dedicated HANA machine type, 7DJUCTO1WW, and the two-socket SR650 V4 has its own, 7DLN. Certification does not force the socket count — database size does.
What are the SR850 V4 machine types?
Three base configure-to-order models: 7DJSCTO1WW with three-year base warranty, 7DJTCTO1WW with one year, and 7DJUCTO1WW for SAP HANA configurations with three-year warranty. The two-year warranty gap between the first two is worth checking carefully on a machine at this price.
Related
- SR630 V4 vs SR650 V4 — the same density-against-expansion trade, one level down
- HPE four-socket scale-up — DL580 Gen12 against two DL380, and why 4U buys only memory
- Memory population rules — 64 DIMM slots only help if they are populated correctly
- MTM and part numbers — 7DJS, 7DJT and 7DJU, and what separates them
- Model numbers decoded — why 850 and 860 sit where they do in the range
- Sizing an HCI cluster — the arithmetic that usually points to scaling out
- Server refresh and consolidation — where rack power becomes the binding constraint
- How to choose Lenovo ThinkSystem servers · stock, lead times and pricing
Sources
- Lenovo Press — ThinkSystem SR850 V4 product guide (2U four-socket, Xeon 6700-series with up to 86 cores per socket, 64 DIMM slots and 16 TB, 6400 MHz at 1 DPC, up to 24× 2.5″ or 32× E3.S, up to 9 PCIe slots plus two OCP 3.0, machine types 7DJSCTO1WW, 7DJTCTO1WW and 7DJUCTO1WW for SAP HANA)
- Lenovo Press — Introducing the SR850 V4 and SR860 V4 for large memory workloads (both four-socket, 16 TB of 6400 MHz DDR5, positioned for SAP HANA, in-memory databases and scale-up; SR860 V4 at 4U with up to 18 PCIe slots, four double-wide GPUs and up to 48 drive bays)
- Lenovo Press — ThinkSystem SR860 V4 product guide
- Lenovo Press — ThinkSystem SR650 V4 product guide (the two-socket comparison point: 86 cores, 32 DIMM slots, 8 TB, 10 rear PCIe slots, two OCP, machine type 7DLN for SAP HANA)