LGA 1851 socket: CPUs, chipsets and cooler fit

What changed from LGA 1700

Three things changed at once. The socket and chipset generation are new, memory is DDR5 only, and the processors dropped Hyper-Threading: the Core Ultra 7 265K, for example, has 20 cores and 20 threads. The Arrow Lake design also moved to a tile based package built partly by an outside foundry, which is a manufacturing choice and does not affect which board you buy.

For a buyer the checklist is short. Pick an 800 series board, buy DDR5 memory, and confirm that your cooler lists LGA 1851 or LGA 1700 support. If you are coming from LGA 1700, the cooler is the one part you may be able to keep.

Choosing among the 800 series chipsets

Z890 is the board family for anyone who wants to change CPU multipliers on K-series processors. B860 is the usual choice for a build that stays at stock speeds, and it still allows memory overclocking. H810 sits at the bottom of the range and trims features to save cost. Q870 and W880 target business and workstation systems.

Intel released the Core Ultra 200S Plus refresh in March 2026 for the same boards. The company's own chipset pages list the Core Ultra 7 270K Plus and Core Ultra 5 250K Plus as compatible, which confirms that no new socket or chipset series was needed.

Memory and PCIe

Official memory speed depends on the processor. The Core Ultra 7 265K, for example, is rated for DDR5-6400, and the Plus refresh raises the official figure further. Boards often support higher speeds with overclocking profiles, so the board's memory support list matters more than the processor's rated figure.

The processor provides 20 PCIe 5.0 lanes, split into an x16 link for graphics and an x4 link for storage, plus 4 PCIe 4.0 lanes. That is more CPU attached bandwidth than LGA 1700 offered. On boards that wire it this way, the PCIe 5.0 x4 link and the PCIe 4.0 x4 link can each serve an NVMe drive.

How long the socket will last

How long LGA 1851 stays current depends on Intel's roadmap. The next desktop generation, Nova Lake, is reported to use a different socket called LGA 1954, and at the time this page was checked no processor for it had been released. That makes LGA 1851 the current Intel desktop socket today and likely the previous one before long. A build on it still has a clear upgrade path from a Core Ultra 5 to the top Core Ultra 9 and the Plus models, which all use the same board.