Intel LGA3647: The Complete CPU List

This LGA3647 CPU list covers every processor made for Socket P: the first two generations of Xeon Scalable (Skylake-SP from 2017, Cascade Lake from 2019 and its 2020 refresh), the Xeon W-3175X and the W-3200 workstation chips, plus the OEM and cloud models that fill the second-hand market. Use the filters to narrow it down by generation, tier, core count, TDP, socket count or features, or type a model number or the sSpec code printed on the CPU into the search box.

Two generations, one socket

The model number tells you almost everything. The first digit is the tier: 8 for Platinum, 6 and 5 for Gold, 4 for Silver, 3 for Bronze. The second digit is the generation: 1 for Skylake-SP, 2 for Cascade Lake. So the Gold 6148 and Gold 6248 are the same class of chip, one generation apart.

• Platinum scales to 8 sockets over 3 UPI links. Gold 6000 goes to 4 sockets with 3 UPI links, Gold 5000 to 4 sockets with 2. Silver and Bronze stop at 2 sockets. Some models go lower: F models and a few Gold chips such as the 6222, 6262 and 6269Y are limited to 2 sockets, U models to one. The Sockets column shows the limit for each chip.
• AVX-512: Platinum and Gold 6000 have two FMA units per core; Gold 5000, Silver and Bronze have one. A few models break the rule (the Gold 5122, 5222 and 5219Y have two, the Gold 6122 one), so use the 2× AVX-512 FMA filter. With one unit, peak AVX-512 throughput per clock is half that of a two-unit chip, no better than AVX2.
• Bronze has no Turbo Boost and no Hyper-Threading in either generation.
• Cascade Lake brought faster memory (DDR4-2933 on most Gold 6200 and all retail Platinum 8200 chips, up from 2666), 1 TB per socket instead of 768 GB on standard models, Optane DC Persistent Memory support and the VNNI (DL Boost) instructions.
• The 2020 refresh (models ending in R) gave more cores and higher clocks for the money. In exchange, the Gold 5200R and 6200R run in 2-socket systems only, and the 6200R lost its third UPI link.

OEM and cloud CPUs

Intel built special versions of Xeon Scalable for the big cloud operators. They never went on retail sale and have no page on Intel’s site, but thousands came onto the market when the servers were retired, and they are among the cheapest ways to get 18 to 28 cores on this socket. Amazon used the Platinum 8124M and 8275CL in its compute instances (c5) and the 8175M and 8259CL in its general-purpose ones (m5). Microsoft Azure used the 8171M and 8272CL, Alibaba Cloud the 8163 and 8269CY, and Tencent the Gold 6133.

The risks come from the missing documentation:

• Board support is not guaranteed. The Cascade Lake cloud chips have the best record: 8272CL, 8275CL, 8269CY and 8255C owners have posted CPU-Z validations with turbo working on the stock BIOS of Supermicro, ASRock Rack, ASUS, HPE and Dell boards. The 240 W Skylake chips are hit and miss: an 8124M would not start on a Supermicro X11DPH-T with any BIOS its owner tried, nor an 8175M on an X11SPi-TF, while ASRock Rack C621 boards ran the 8124M fine.
• Power. Several of these chips are rated 240 W, and most LGA3647 boards are built for 205 W at most.
• Specs vary between sources. Without an Intel page, clocks and even the sSpec of some models (the 8171M, for one) differ from listing to listing. Check the sSpec on the photo of the CPU lid: the 8259CL, for example, is SRFA8.

Before buying, search for the exact model together with your board’s name, and prefer sellers who show a CPU-Z screenshot from an off-the-shelf board.

Will it run on my board?

• BIOS for Cascade Lake. Both generations share the C620-series chipsets (C621, C622, C624 and so on), but a board made for Skylake-SP needs a BIOS update before a Cascade Lake CPU will start. On Supermicro X11 boards that means BIOS 3.0a or newer, and some models need 3.2 for the 2020 R chips. Check the board’s CPU support list.
• Power limit. Boards are rated for a maximum CPU TDP. The Supermicro X11SPi-TF, X11DPi-N and ASUS WS C621E SAGE take up to 205 W, the X11SPL-F only 165 W and the X11DPL-i 140 W. Most Xeon Scalable chips are rated 205 W or less, but the Platinum 8274 and 8284, the Gold 6269Y and several OEM chips are rated 240 W.
• Xeon W boards. The W-3175X and W-3200 use the same socket but are single-socket chips that won’t run on just any LGA3647 board. The W-3175X (255 W, unlocked) runs on boards built for it, such as the ASUS ROG Dominus Extreme and Gigabyte C621 AORUS XTREME, which also take ordinary unbuffered memory. Supermicro, for one, states that its 205 W X11DPH-T won’t start with it. The W-3200 runs on boards that list it, such as the Supermicro X11SPA-T and ASUS Pro WS C621-64L SAGE, which also take Xeon Scalable. Don’t assume a server board runs either.
• Cooler mount. LGA3647 boards use one of two retention frames (ILM): Narrow, the more common in servers, or Square. The CPU fits both, but the heatsink must match the board, Narrow with Narrow, Square with Square. The CPU clips into a plastic carrier on the heatsink; the carrier comes with the board and also differs between Narrow and Square. Some coolers, such as Noctua’s DX-3647 series, include brackets for both.
• F models. The Omni-Path tab on the side of F chips needs a separate fabric carrier clip, and the board must support F models, with a retention clip for the fabric cable and extra power circuitry. Supermicro has dropped F-model support from all its X11 boards, and on a board without it such a chip may not boot.
• Memory. Each CPU has six DDR4 channels and takes registered ECC memory only, RDIMM or LRDIMM. Xeon Scalable boards don’t support desktop UDIMMs; the W-3175X boards above are the exception.
• Two sockets. For a dual-socket build, buy two of the same model.
• Not the same socket. The Xeon Phi x200 is built for a different LGA3647 variant, P1, while Xeon Scalable uses P0. The keying differs, so a Xeon Phi won’t fit a Xeon Scalable board, and vice versa. The Platinum 9200 doesn’t go in a socket at all: it is soldered to the board (BGA). The 3rd gen Xeon Scalable moved to LGA4189, in two incompatible versions: one for Cooper Lake (Platinum 83xxH, Gold 53xxH and 63xxH) and one for Ice Lake.
• Chinese boards. Huananzhi lists dual-socket C621 boards for both generations: the X11D-16D, with six memory channels per CPU, and the X11D-8D, which wires only four.

Which CPU to choose

• The most cores for the money: the Cascade Lake cloud chips. The 8272CL (26 cores, 195 W) has the best record on retail Supermicro boards; the 8259CL (24 cores) and 8275CL (24 cores, 3.9 GHz turbo, 240 W) are common too. Check the board’s power limit first.
• Retail chips with the 2020 price cut: the Gold 6230R (26 cores) and 6240R (24 cores) give many cores at 150 to 165 W. They need a BIOS that supports the 2020 refresh and are 2-socket only.
• On an old Skylake BIOS: the Gold 6148 (20 cores, 150 W) and 6138 (20 cores, 125 W) need no BIOS update at all.
• Single-socket workstation: a W-3200 on a board that supports it gives 64 PCIe lanes and up to 4.6 GHz. The W-3175X is the only chip on this socket with an unlocked multiplier, but it runs only on a few boards built for it (ASUS ROG Dominus Extreme, Gigabyte C621 AORUS XTREME, EVGA SR-3 Dark) and needs serious cooling.
• Coming from X99: next to the Xeon E5 v3/v4 in our LGA2011-3 guide, this platform adds two memory channels per CPU, AVX-512 and up to 28 cores per socket, but the boards and registered memory cost more.
• Skip the Bronze chips (no turbo, no Hyper-Threading), and skip F models unless your board supports them.

Engineering and qualification samples (ES/QS, with a Q-code such as QQ89 in place of the sSpec) are not in the table. They are pre-production chips that Intel never sold, which means no warranty, and clocks and features can differ from the retail model. Board support is the bigger risk: Supermicro’s X11 BIOS for Cascade Lake dropped support for early Skylake pre-production steppings, so a BIOS update can leave such a chip unable to boot, and the only fix is an older or modified BIOS.

The same Skylake and Cascade Lake cores in a single-socket desktop platform: our LGA2066 CPU list covers the Core X-series for X299 and the Xeon W-2100 and W-2200 for C422.

FAQ

Will my Skylake board run Cascade Lake?

In most cases, yes. Board makers released BIOS updates that add 2nd gen Xeon Scalable support to C621 boards built in 2017 and 2018. Without the update a Cascade Lake chip won’t start, so flash the new BIOS while the old Skylake CPU is still in the board. If the maker never released such a BIOS for your model, the board has no official Cascade Lake support.

Which Windows do I need, and does it run Windows 11?

Windows 10 Home and Windows 11 Home use only one CPU socket, Pro uses two, and Pro for Workstations up to four, so a dual-socket build needs at least Pro. Pro also caps memory at 2 TB, Pro for Workstations at 6 TB. Both generations of Xeon Scalable and the W-3100 series (the W-3175X) are on Microsoft’s list of processors supported by Windows 11. The W-3200 is not named, although it uses the same Cascade Lake cores as the listed 2nd gen Xeon Scalable.