Monday, July 1st 2024
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.
Sources:
HXL (Twitter), ChipHell Forums
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 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.
36 Comments on Intel Core Ultra "Arrow Lake" Desktop Platform Map Leaked: Two CPU-attached M.2 Slots
Maybe even offer the ability for choosing between a front PCIe slot or an M2 slot behind, similar to how using an M2 drive in one slot disables a SATA port or two, or decreases the speed due to alternating data between both the M2 and SATA drives (varies by motherboard; some disable, others just reduce data speeds).
The fifth NVMe is moved in a temporary(permanent?) position, with the help of a PCIe riser extension cable, so I could use that PCIe slot that was covered by the graphics card. The motherboard is the X470 GAMING PLUS MAX. Obviously some NVMe's are connected through PCIe X1, but even that way they are a better option than a typical SATA SSD.It's more like 3+ euros than less than 1. I think that price is for new members. Of course that doesn't change the fact that a PCIe slot can house an NVMe SSD perfectly with a very small extra cost, a cost that the motherboard manufacturer could cover considering the prices of modern motherboards.
And of course having an extra X16 slot, means that something like this can also be used
PCIe X16 To X8+X4+X4 Splitter Card Adaptor M.2 NVMEx2 Input Ports Adapter Card Expansion Card Support 2280/2260/2242/2230 SSDThey are needed to make the motherboard look expensive and good looking. Remove them and the truth reveals itself. An empty PCB. Who would pay 400 euros/dollars for a big empty PCB?
I personally run multiple PCIe expansion cards (sound card, HBA, NIC, etc).
Thankfully my NVMe U.2 drives come with cables for m.2 slots.
It's all down to which interfaces individual users need more.
pg.asrock.com/mb/AMD/X670E%20PG%20Lightning/index.asp
The X470 MSI that I am using costed me 90 euros. But it was a very good price to be fair. Let's say it's standard cost was 120 euros 5 years ago, so probably less than 200 today. Two PCIe x16 slots connected to the CPU with the option to work as x8 + x8.
The ASRock in the above example only connects one PCIe slots to the CPU. The other 3 slots are connected to the chipset and only one of the PCIe x16s is X4, the other is X1. And the price in Greece for the ASRock is around 260 euros. We pay more, we get less. There are options but all feel - from my perspective at least - like scams. That's why I am describing those as "microATX boards in ATX form", because they look like being designed as microATX boards and then manufacturers just add a little more PCB for a couple of X1 slots or M.2 slots while also doubling the final price of the product.
- there are such boards, even with two Gen5 slots, despite the fact that no one in the world can make any meaningful use of two Gen5 slots
- if I was motherboard vendor, I would not be offering two Gen5 slots and other chipset slots either; waste of material
- you can blame Intel and AMD pushing for PCIe 5.0 adoption three years too early, when we would not have Gen5 GPUs until next year
That is because the 10Gbit card I use on my desktop systems is a X520-DA1 which is a Gen2 card with 8 lanes. Having a slot with 4 lanes of Gen2+ would be fast enough.
These cards are pretty inexpensive and very well supported in all OS-es because they date from 2011. Never had issues with them. And they low-power too.
Intels cards have less issues and better support than Aquantia (especially since they were taken over by Marvell).
Most controllercards available today are still Gen2 & Gen3 and that is changing only very slowly.
An example of why I feel I need extra slots (preferably some with 4 lanes besides slots with just 1 or 2 lanes).
In future I might (need to) add an NPU card. The latest processors have a dedicated npu even though they have graphics on board.
And since AI is developing very fast I might need to upgrade it to a faster version that needs a wider and faster slot.
I do agree that a basic desktop system for the average user, based on an apu or laptop processor doesn't need many slots.
Being able to add 2 M2's and 1 or 2 cards is probably enough for that use-case.
Just have a look at the mobo I chose. Three M.2 slots and three extra PCI-E x16 slots (x4 electrically). All of these are Gen4 and you can use them all at the same time!