Intel LGA1851 Socket and Z890 Platform

With the Core Ultra 2-series "Arrow Lake-S," Intel is debuting a new socket, LGA1851. You will hence require a new motherboard to go with your shiny new processor, and since all processor models Intel is launching this year are unlocked K or KF SKUs, the only motherboard chipset model available will be the top-spec Intel Z890. Intel will flesh out its processor model stack in 2025, and with it, launch more affordable motherboard chipsets.

The "Arrow Lake-S" SoC puts out a dual-channel DDR5 memory interface, which we described in the previous pages. It also features a massive 48 platform PCIe lanes (CPU + chipset). Intel has increased the number of PCIe Gen 5 lanes put out by the CPU to 20—that's 16 lanes meant for the PEG (x16 slot for graphics cards), and one CPU-attached M.2 NVMe slot that runs at Gen 5 speeds without eating into the 16 PEG lanes. The CPU puts out a second set of Gen 4 x4, which can be wired out as an M.2 slot, or be used to drive high-bandwidth onboard devices, such as a discrete Thunderbolt 5 controller. The processor itself fully integrates a Thunderbolt 4 controller, which puts out a couple of 40 Gbps ports.


The processor connects to the Z890 chipset over a DMI 4.0 x8 chipset bus (bandwidth comparable to PCI-Express 4.0 x8). It puts out 24 PCI-Express Gen 4 downstream lanes. This is a massive increase from the Z790, which put out 16 Gen 4 and 8 Gen 3 lanes. The integrated USB complex consists of 32 USB 3.2 5 Gbps serial-deserializers, which can be configured by motherboard designers into five 20 Gbps ports, ten 10 Gbps ports, and ten 5 Gbps ports. There's also a 14-port USB 2.0 hub. Intel has retired the HDA "Azalia" audio interface with Z890, which means onboard audio CODECs will have to use the newer MIPI SoundWire and USB 3.2 interfaces (which CODECs like the Realtek ALC4080 and ALC4082 already do).

The chipset integrates a 1 GbE MAC, and Wi-Fi 6. With the PCIe and USB 3.2 connectivity on offer, motherboard vendors can go bonkers with network connectivity, by giving their platforms Wi-Fi 7 and 2.5 GbE, or even 5 GbE and 10 GbE. Vendors can opt for Intel's Killer networking package, which combines existing Intel networking PHY with the advanced Killer prioritization engine, and DoubleShot Pro, which work together to reduce network latency when gaming.


Intel has revamped the security architecture for its client processors with "Arrow Lake," giving them three separate hardware security engines, including a purpose-built Converged Security and Manageability Engine (basically the Intel ME but with added security roles), the Silicon Security Engine, which is microarchitecture-level hardening for the new Lion Cove and Skymont CPU cores, a new dedicated security controller for the iGPU, and compliance with Microsoft Secured Core.