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.

We've known for a while that the Z890 will be Intel's next-generation high-end desktop motherboard chipset for the Core Ultra "Arrow Lake-S" desktop processors in the LGA1851 package, and that Intel's first wave of processors and motherboards will target PC enthusiasts like they usually do—with just the unlocked K/KF processor SKUs and motherboards based on the Z890. We are now learning that the B860 will indeed be the company's mid-tier chipset for the processor. MSI has registered at least four motherboard models based on the B860, which showed up on Device Report.

These four motherboard models are the MPG B860M Edge Ti WiFi, the MPG B860I Edge WiFi, the MAG B860 Tomahawk WiFi, and the MAG B860M Mortar WiFi, with MSI internal product numbers 7E38, 7E39, 7E40, and 7E43, respectively. There's no word on whether B860 will even be available when the processors debut. Going by past trends, the mid-tier chipset and 65 W-class processor SKUs usually come out in the Q1 following a new processor generation launch, which means we could see these sometime early-2025. The B860 will lack CPU overclocking capabilities, and probably feature a narrower chipset bus, and fewer PCIe general purpose lanes than the Z890. As for MSI's Z890 motherboard lineup, there are at least eight models recorded—the MEG Z890 GODLIKE, the MEG Z890 Ace, MEG Z890 Unify-X, MPG Z890 Carbon WiFi, MPG Z890 Edge Ti WiFi, MPG Z890I Edge Ti WiFi, MAG Z890 Tomahawk WiFi, and the PRO Z890-P WiFi.