https://www.techpowerup.com/324025/intel-core-ultra-arrow-lake-desktop-platform-map-leaked-two-cpu-attached-m-2-slots Intel's upcoming Core Ultra "Arrow Lake-S" desktop processor introduces a new socket, the LGA1851, alongside the new Intel 800-series desktop chipset. We now have some idea what the 151 additional pins on the new socket are used for, thanks to a leaked platform map on the ChipHell forums, discovered by HXL. Intel is expanding the number of PCIe lanes from the processor. It now puts out a total of 32 PCIe lanes.
From the 32 PCIe lanes put out by the "Arrow Lake-S" processor's system agent, 16 are meant for the PCI-Express 5.0 x16 PEG slot to be used for discrete graphics. Eight are used as chipset bus, technically DMI 4.0 x8 (these are eight lanes that operate at Gen 4 speed for 128 Gbps per direction of bandwidth). There are now not one, but two CPU-attached M.2 NVMe slots possible, just like on the AMD "Raphael" and "Granite Ridge" processors. What's interesting, though, is that not both are Gen 5. One of these is Gen 5 x4, while the other is Gen 4 x4.
The system agent has two kinds of PCIe root complexes, just like it did on Socket LGA1700 processors. The new "Arrow Lake-S" has 20 lanes of Gen 5, and 12 lanes of Gen 4, which is how it's able to put out a Gen 5 x16 PEG, a Gen 5 x4 M.2; a DMI 4.0 x8 chipset bus, and an additional CPU-attached Gen 4 x4 M.2. In comparison, "Alder Lake-S" and "Raptor Lake-S" feature 16 lanes of Gen 5, and 12 lanes of Gen 4, leaving the platform with no CPU-attached Gen 5 M.2 slots, unless you subtract them from the Gen 5 x16 PEG slot, which is what all motherboard designers have done. There will be no such problem with "Arrow Lake-S."
The two CPU-attached x4 links can be wired out as M.2 slots, but it's also possible that the Gen 4 x4 can be used by motherboard designers for certain high-bandwidth devices, such as discrete Thunderbolt 4 or USB4 controllers.
Besides these, the processor has four DDI links for the platform's two Thunderbolt 4 ports (if implemented by the motherboard designer). Intel has updated the display I/O of the platform with HDMI 2.1 and DisplayPort 2.1, although it will probably leave it up to the motherboard designers if they want the latest connectors on even their cheapest motherboard models. There's also an eDP 1.4b connection which should help AIO desktops.
The memory I/O now completely does away with DDR4 support. The platform only supports DDR5, over 2 channels (four sub-channels), along with support for up to two DIMMs per channel. Intel is expected to increase both the native- and overclocked memory speeds for this platform, and we might even see DDR5 memory kits with XMP 3.0 profiles for 10000 MT/s or more. Motherboard vendors can implement standard UDIMMs, compact SO-DIMMs, or even the new CAMM2.
The 800-series chipset in this spy pic, which we're assuming is the top Intel Z890, puts out additional Gen 4 PCIe lanes. There are no more Gen 3-only lanes from the PCH. The chipset also puts out an assortment of USB 3.2 (20 Gbps), USB 3.2 (10 Gbps), and USB 3.2 (5 Gbps) ports, although there's no mention here of 40 Gbps USB4 ports from the platform. And then there are the usual storage and networking I/O, including a few SATA 6 Gbps ports, integrated MACs for 2.5 GbE or 1 GbE wired Ethernet; and Wi-Fi 6E or Wi-Fi 7 CNVi slots.
When they debut in Q4 2024, Intel's Core Ultra "Arrow Lake-S" desktop processors will be accompanied only with the Z890 chipset, since the processor models being launched are expected to be K or KF (unlocked) SKUs. The series will be expanded in early 2025 with non-unlocked processor models, and other chipsets, such as the B860, H870, and H810.
The expansion of PCIe lanes is noteworthy.