Could be quite neat if there was a basic video output too and use a vGPU slice/partition for acceleration.
Bruh… give us motherboards with all 28 PCIe 5.0 lanes. Let us bifurcate down to single lanes and let the third parties make better chipset bundles. Anyone buying a motherboard is doing it for customization, not looking to have all the choices already made for them.
We don’t need AMD to mandate rules for different labels bundles (e.g., X870E must have USB4); their labels suck and force groupings of features that make a worse package deal than if people could choose from a wider selection of individual parts or packages.
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Did ASMedia learned what PCIe Access Control Services are in recent Promontory versions, or you would still get a giant IOMMU Group?
On X670E (and I believe X870E but I only have the former) anything on the first chipset is isolated but anything on the second (daisy chained to first) chipset is bunched together. On my board that is wifi, both ethernet, USB4, 3rd PCIe slot. Kinda sucks.
I think Asock rack has some like that (no chipset) e.g.
https://www.asrockrack.com/general/productdetail.asp?Model=EPYC4000D4U#Specifications
That is a quite interesing revelation. So it DOES support PCIe ACS, just that they don’t even bother to enable it.
Seems like the worst of both worlds. There is no PROM21, but the chipset lanes are nonetheless occupied by a bunch of PCIe 1.0 and PCIe 2.0 devices; you don’t reclaim the PCIe 5.0 lanes for a use of your own choosing.
Folks must be desperate enough to shell out $200 for such an expansion card.
This is true. I despise Promontory and view it as a mediocre, glorified PCIe Switch with SATA and USB built in, yet when I theorycrafted how would I design a Motherboard, there aren’t that many options to replace it because you lose way too many USB ports, keeping only the 4 from the Processor, which aren’t adequate for a desktop. If you kick out Promontory then realize you need to add one or two of the NEC/Renesas XHCI Controllers to add 2-4 USBs back, Promontory seems better at that job. Only exception is if you wanted to rely on an USB Hub chip, but seems like a downgrade. The same happens if you plan to use PCIe 1x NICs like the Intel i225-V 2.5G or Realtek equivalent instead of a 4x one like the Intel X710, E810 or whatever. The moment a PCIe Switch to fanout makes sense, you’re back at Promontory.
I believe getting rid of Promontory is only truly possible in servers because you’re not that dependent on USB Ports. But the ASpeed AST2600 BMC for servers is a PCIe 1x device, so is not like you are going to get a pure 4x link anyways. Reminds me of when EPYC Rome had “extra low speed lanes” to put the BMC in and leave the other 128 for GPUs, NVMe, or whatever instead of butchering an entire 16x link to put a 1x device.
more like the socket has a ton of pins (and the io die has a large controller) so it can fan out PCIe lanes for days and you can connect all sorts of things soldered on the board to that while still having plenty for the slots.
No matter what we do, we always come back to the fact AM4/5 does not have a whole lot of PCIe lanes and it cannot bifurcate below x4, so you must ration them carefully and use a switch to put all the slow stuff on.
By “servers” I mean use, not big EPYC. You have AM5 motherboards with no Promontory intended for server use like the AsRock Rack EPYC4000D4U posted above. The lack of USB Ports doesn’t really hurt those.
Also, AM5 CAN bifurcate to 1x. You can pick the Block Diagram on Page 19 of the EPYC4000D4U manual and notice than a set of 4 lanes goes 1x/1x/1x/1x for an ASMedia 1061 SATA Controller, two Intel i210 NICs and the ASPeed AST2600 BMC.
My comment was pretty much that if you have to bifurcate the 4x link to put the BMC instead of a full 4x device like a 10G Dual Port NIC or a NVMe SSD it isn’t that different from putting Promontory since you aren’t capitalizing on the full 4x link either.
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Unsure - the beauty of what I was thinking is that you’re passing the whole chipset on a card thru as a PCIE device.
How I would use it is to have my daily PC just running as a VM on my server, but it would need that basic video out and then pass thru a GPU slice for the actual acceleration.
It is rather expensive.
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Mine would be proper HEDT. 12-32 cores, quad channel memory and 48 PCIE lanes (32 gen 5 and 16 gen 3 to reduce costs).
Since it can be related, I’ll crosspost another sighting of a possibly B650 card on aliexpress