Intel Xeon W-3175X socket: LGA 3647
The Intel Xeon W-3175X uses the LGA 3647 socket on C621 workstation boards. It is an unlocked 28 core single socket chip for high end workstations.
- Socket
- LGA 3647
- Launched
- January 2019
- Cores and threads
- 28 and 56
- Base power
- 255 W
- Codename
- Skylake-W
- Segment
- Workstation
- Family
- Intel Xeon W
- Clocks
- 3.1 / 4.3 GHz
Intel Xeon W-3175X specifications
| Cores | 28 |
|---|---|
| Threads | 56 |
| Core architecture | Skylake-W cores on 14 nm |
| Clocks | 3.1 GHz base, up to 4.3 GHz with Turbo Boost 2.0 |
| Cache | 38.5 MB Intel Smart Cache (L3) |
| Processor base power (TDP) | 255 W |
| Manufacturing process | 14 nm |
| Memory support | DDR4-2666 ECC, six channels, up to 512 GB |
| PCI Express | 48 lanes from the CPU, PCIe 3.0, plus platform lanes from C621 |
| Integrated graphics | None, discrete GPU required |
| Multiplier | Unlocked |
| ECC memory | Supported |
| Package | FCLGA3647 (76.0 by 56.5 mm) |
Motherboard and chipset compatibility
Intel Xeon W-3175X needs a motherboard with a LGA 3647 socket. The table shows which chipset series accept it.
| Series | Chipsets | Support |
|---|---|---|
| C621 workstation | C621 | Works out of the box |
Board makers publish a CPU support list for every model. Check it for your exact board before buying. Chipset details for LGA 3647.
LGA 3647 at a glance
| Type | LGA, 3,647 contacts |
|---|---|
| Package size | 76.0 × 56.5 mm |
| Introduced | 2016 |
| Memory | DDR4-2933 ECC, six channels, up to 2 TB |
| Cooler mounting holes | Board specific (narrow and square ILM heatsinks) |
What the Xeon W-3175X is
The Xeon W-3175X packs 28 cores and 56 threads into a single socket workstation envelope. It launched in January 2019 with a 3.1 GHz base and up to 4.3 GHz boost at 255 W. Intel positions it as the flagship for creators who need server silicon without dual socket complexity.
Thirty eight point five megabytes of shared L3 cache feed rendering and simulation threads across all cores. The high core count suits parallel exports, while boost holds single thread speed for interactive modeling. Hyper-Threading doubles thread slots for mixed workloads.
The process is 14 nm and the multiplier is unlocked for tuning where the board allows it. There is no integrated graphics, so a discrete GPU is required for display output. ECC memory is supported, which matters for long renders where a flipped bit would waste hours.
Socket and motherboard compatibility
The W-3175X fits the LGA 3647 socket on C621 workstation boards only. Makers such as ASUS and Gigabyte list it with single socket C621 boards that provide six channel memory and robust power delivery. Server LGA 3647 boards with different firmware do not support the unlocked workstation features.
Six channel DDR4 ECC memory up to 2666 MT per s carries up to 512 GB on workstation boards that list the part. Population follows board rules for one DIMM per channel at full speed. The Socket vs chipset: what decides whether a CPU works guide explains why workstation compatibility lives in board vendor lists.
LGA 2066 Xeon W parts cannot move to this socket. The contact count and package size differ entirely. Upgrading within LGA 3647 means another Skylake-W SKU where the board support list includes it.
Memory, PCIe and cooling
DDR4-2666 ECC in six channels is the workstation memory for this generation. Matched kits across six slots give full bandwidth near 128 GB per sec for large scenes. Builders who work with 8K footage should order 128 GB or more from the start, since RDIMM pricing dominates many builds.
PCIe arrives as 48 Gen3 lanes from the CPU for GPUs and NVMe, plus platform lanes from C621 for storage and I/O. Typical boards split lanes between two graphics slots and multiple M.2 slots. Exact wiring follows the board design, so check the maker block diagram for lane sharing.
Cooling for 255 W needs vendor qualified liquid or large air with strong chassis airflow. The 76.0 by 56.5 mm package uses a carrier frame and screws down through the heatsink, with no lever retention. Torque sequence follows the board maker manual rather than a generic cooler guide such as the CPU cooler compatibility by socket overview.
Upgrade paths
On the same socket, lower core Xeon W-3200 parts such as 18 and 24 core SKUs drop power and price for smaller thermal budgets. They fit the same C621 boards after a BIOS check. The W-3175X remains the ceiling for single socket core count in this generation.
Workstation builders who need dual sockets should look at Xeon Scalable on server LGA 3647 boards instead. Those platforms trade the unlocked multiplier for two socket scaling and larger memory footprints.
Past LGA 3647 a new board is required, since later Xeon W families moved to LGA 4677 and newer sockets. The W-3175X covers single socket workstations where 28 cores must run for years, and only a platform move justifies replacing it.
Frequently asked questions
What socket does the Intel Xeon W-3175X use?
It uses LGA 3647 on C621 workstation boards, written FCLGA3647 in Intel documents.
How many cores does the W-3175X have?
Twenty eight cores with Hyper-Threading give 56 threads. Base is 3.1 GHz with boost to 4.3 GHz.
Does the W-3175X include integrated graphics?
No. It needs a discrete GPU for display output. Workstation cards pair well for rendering and CAD.
What memory does the W-3175X support?
DDR4-2666 ECC in six channels up to 512 GB. ECC is supported for error correction.
When did the W-3175X launch?
January 2019 as the 28 core flagship of Xeon W-3200 for single socket workstations.
Sources and verification
- Intel Xeon W-3175X Processor specifications (Intel)
- Intel Xeon W-3175X specs (TechPowerUp)
- LGA 3647 on Wikipedia
Facts last checked against these sources on . Page last edited on .