why no manufacturer releases without PCH AM5 motherboards?

[rage1234560]

5 usb / 28 pcie lanes provided by the CPU I/O die should be enough for most people

although x600 deskmini/deskmeet is coming soon

but they are not sold as standalone motherboards

I really want a without PCH ITX/MATX motherboard

 

[Assimilator]

Probably because the only thing motherboard manufacturers are capable of nowadays, is adding more RGB. Making smart use of a platform's features, what's that?

 

[DarkDreams]

Because you would have no networking, no sata and no audio. That all goes through the chipset unless I am mistaken.

 

[rage1234560]

Because you would have no networking, no sata and no audio. That all goes through the chipset unless I am mistaken.

zen laptop/deskmini/deskmeet(x300) are without pch but still have networking/sata/audio

 

[TheLostSwede]

Because you would have no networking, no sata and no audio. That all goes through the chipset unless I am mistaken.

Ethernet is via PCIe, so it'd eat up one lane. The audio is via the CPU, but SATA has moved entirely to the chipset on AM5.

zen laptop/deskmini/deskmeet(x300) are without pch but still have networking/sata/audio

AM4 and AM5 are not the same when it comes to these interfaces.

 

[tabascosauz]

AM4 and AM5 are not the same when it comes to these interfaces.

Sure but Ryzen is still an SoC, is it not? That's what enables all that connectivity without a PCH, on X300 or laptops for example.

The chipset uplink to CPU is also basically the same as it used to be, it's not robbing a whole bunch more lanes.

 

[TheLostSwede]

Sure but Ryzen is still an SoC, is it not? That's what enables all that connectivity without a PCH, on X300 or laptops for example.

The chipset uplink to CPU is also basically the same as it used to be, it's not robbing a whole bunch more lanes.

I didn't say it was impossible, I simply clarified that the two platforms are different.

 

[mouacyk]

$$$
they're not your friend

 

[LabRat 891]

I seem to recall there was supposed to be an A-series 'platform' that've filled this need...

 

[Assimilator]

Because you would have no networking, no sata and no audio. That all goes through the chipset unless I am mistaken.

All of these can be provided via add-in chips.

 

[Deleted member 232534]

5 usb / 28 pcie lanes provided by the CPU I/O die should be enough for most people

although x600 deskmini/deskmeet is coming soon

but they are not sold as standalone motherboards

I really want a without PCH ITX/MATX motherboard

because you would need separate controllers for all the o/i

am4 had x300 chipset for sff systems

 

[LabRat 891]

because you would need separate controllers for all the o/i

am4 had x300 chipset for sff systems


View attachment 310071

This would seem to reinforce the plausibility of a PCH-less AM5 platform. (I could've sworn AMD 1st party block diagrams had switchable SATA/PCIe right off the SoC?)
Instead of a PCH, a cheap old Gen3 PCIe Switch would be more than sufficient to attach NIC, WiFI/BT, and SATA.


It's not even really needed at all; it could be done off the on-SoC USB (instead of PCIe).
(I've seen similar done in old Netbooks and descendants)

 

[Deleted member 232534]

This would seem to reinforce the plausibility of a PCH-less AM5 platform. (I could've sworn AMD 1st party block diagrams had switchable SATA/PCIe right off the SoC?)
Instead of a PCH, a cheap old Gen3 PCIe Switch would be more than sufficient to attach NIC, WiFI/BT, and SATA.


It's not even really needed at all; it could be done off the on-SoC USB (instead of PCIe).
(I've seen similar done in old Netbooks and descendants)

ok, what is the cost of B650 pch?

 

[LabRat 891]

ok, what is the cost of B650 pch?

Sadly, that information doesn't seem to be consumer-facing. (At least, it's not coming up through search engines) I'm curious, myself.

I'm basing my presumptions off commentary-over-time regarding 'how much the Promontory adds to BOM'.

Also, I've (clearly) been out of the loop; I see A620* has hit the market. Those boards are still kinda spendy, though.

edit:*A620 is the 'stripped down' version of AMD Promontory 21, the same PCH used for the B650 and used in multiple on X670(E).

 

[TheLostSwede]

because you would need separate controllers for all the o/i

am4 had x300 chipset for sff systems

X300 was chipset-less. It was kind of the whole point of the platform. It did have a Super I/O chip though and some other bits to make it fully functional.

 

[LabRat 891]

X300 was chipset-less. It was kind of the whole point of the platform. It did have a Super I/O chip though and some other bits to make it fully functional.

Was about to add...
Igorslab uncovered PCH-less support in AM4 SoCs prior to the X300, A300, and PRO 500 platforms' release.
AMD called it "Knoll Express".

AM4 SoCs and AM5 SoCs are indeed different. However, I have difficulty believing AMD would remove a feature specifically attractive to ODMs and partners.

Additionally, (as mentioned in OP) "X600" platform should be appearing soon in the form of the AsRock DeskMini. (The 'rumors' are heavily substantiated by regulatory/shipping documents)
I wouldn't be surprised to see Minisforum (and other 'known' mini-PC brands) making their own X600/A600 platform boxes.

 

[Assimilator]

ok, what is the cost of B650 pch?

It's not so much the cost as it is the heat output and physical footprint. Discrete USB, ethernet, and SATA controllers each put out less heat than a chipset and are smaller, so the manufacturer has more options for positioning them around the board - especially important in space-constrained applications like mITX.

 

[LabRat 891]

It's not so much the cost as it is the heat output and physical footprint. Discrete USB, ethernet, and SATA controllers put out less heat than a chipset and are individually smaller, so the manufacturer has more options for positioning them around the board - especially important in space-constrained applications like mITX.

I'm not a board designer or EE but... AFAIK typically, 'highly integrated' designs are considered 'more (space, power, heat) efficient'.

In-context however, the only thing(s) really missing off the Desktop SoC is Ethernet (and SATA).
I was mixing up the mobile SoC w/ Desktop, earlier. Some Mobile Ryzen slides show SATA on-SoC

Audio, USB, PCIe, etc. are all on-SoC.

AMD/ASMedia PROM21 looks like a PCIe Gen4 Switch, USB 10gbps and SATA Controller 'integrated' together.
Which, is highly 'efficient' *if* you need that I/O.

Ethernet, WiFi/BT, etc. were already PCIe attached, 'externally' (relative to the SoC and PROM21).

For SFF PCs, 'Appliance' PCs, and Industrial/Automation application, the SoC alone isn't missing much. PROM21 simply isn't needed in many boards' design.
On that note, considering the prevalence of cheap NVMe drives, is SATA even really needed?
-On ITX/SFF, SATA drives are undesirable bulk. Industrial M.2 NVMe exists, and legacy storage inter-compatibility could be accomplished over USB or Riser+add-in card.
-Anything SSI-(EEB, MEB, TEB), XL-ATX, E-ATX, ATX, mATX, can add SATA via an x1, x4, or M.2 interface PCIe card.
In the future, I could see some Chinese company make PCH-less AM5 boards, using eWaste-salvage PCIe Switches and Bridges for custom cheapo server/gamer boards. They've already done similar for at least 3 or 4 generations of long gone-by 'higher end' platforms. (I'm assuming AMD will do something like they've done w/ OEM fuse-blow-locking and actively prevent eWaste Salvage and re-use of PROM21s)

That leaves us needing an Ethernet Controller, same as a PROM21-equipped board: There's a lot of small-footprint, low-power PCIe x1-x4 Ethernet controller options. Including, dual-port 10GBASE-T and Multi-Gig(2.5-5) ethernet controllers, for eventual SFF Industrial/Network Appliance use. If one were trying to go as low-cost as possible, I believe there are also USB(5/10gbps)-attached gig and multi-gig Ethernet controllers.

 

[TheLostSwede]

Was about to add...
Igorslab uncovered PCH-less support in AM4 SoCs prior to the X300, A300, and PRO 500 platforms' release.
AMD called it "Knoll Express".

AM4 SoCs and AM5 SoCs are indeed different. However, I have difficulty believing AMD would remove a feature specifically attractive to ODMs and partners.

Additionally, (as mentioned in OP) "X600" platform should be appearing soon in the form of the AsRock DeskMini. (The 'rumors' are heavily substantiated by regulatory/shipping documents)
I wouldn't be surprised to see Minisforum (and other 'known' mini-PC brands) making their own X600/A600 platform boxes.

Well, the loss of SATA in the CPU shouldn't be a big deal to be honest, at least not as the CPU got more PCIe lanes in total.
I guess we'll just have to wait and see if there's an X/A600 or whatever at some point.

 

[Assimilator]

I'm not a board designer or EE but... AFAIK typically, 'highly integrated' designs are considered 'more (space, power, heat) efficient'.

When's the last time you saw a discrete USB, SATA or non-10GbE ethernet controller that needs a heatsink? That's one of the design goals of those chips.

Integration has a drawback, namely that you're cramming all the functionality of those components into a space that is smaller than the sum of its parts, which means more heat with less surface area to dissipate it, hence the requirement for chipset heatsinks.

On that note, considering the prevalence of cheap NVMe drives, is SATA even really needed?

A good question. However, the way I see it is this:

• Zen 5's 8 general-purpose PCIe lanes are split into two groups of 4
• Therefore, if you want to use any 1 of those lanes, you're committed to using all 4 from a group
• Given that it makes sense to use all of them, and the most logical way IMO to do so is to basically replicate the Prom21 functionality:
  • 1 lane for ethernet (possibly 10GbE)
  • 1 for WiFi
  • 1 for audio
  • 1 for SATA or USB

 

[bug]

All of these can be provided via add-in chips.

Maybe, but why validate each add-in (and all of them together) when AMD has already done the work for you in the form of the PCH?

CPU+PCH is the standard platform design, anything else would need substantial demand to allow you to get your costs back.

 

[TheLostSwede]

Maybe, but why validate each add-in (and all of them together) when AMD has already done the work for you in the form of the PCH?

CPU+PCH is the standard platform design, anything else would need substantial demand to allow you to get your costs back.

Unlike Intel, AMD doesn't integrated anything network related into their chipsets. Most likely because they/ASMedia lack the IP/licenses/patents to do so.

 

[bug]

Unlike Intel, AMD doesn't integrated anything network related into their chipsets. Most likely because they/ASMedia lack the IP/licenses/patents to do so.

Be that as it may, AMD's PCH still gives you a bunch of goodies "for free".

 

[Assimilator]

Maybe, but why validate each add-in (and all of them together) when AMD has already done the work for you in the form of the PCH?

CPU+PCH is the standard platform design, anything else would need substantial demand to allow you to get your costs back.

What exactly needs to be validated? The whole point of an add-on controller is to be easily dropped into any system with free PCIe lane(s). Yes, there is integration testing required but it's hardly the mountain you're making it out to be.

 

[bug]

What exactly needs to be validated? The whole point of an add-on controller is to be easily dropped into any system with free PCIe lane(s). Yes, there is integration testing required but it's hardly the mountain you're making it out to be.

How would that work? You add a sound card, network card, a USB card and maybe a SATA controller card? Most motherboards barely have enough PCIe slots to handle all that.
This is usually achieved by integrating the needed controllers and PHYs on the motherboard. It's not rocket science, of course, but it's still work you would have to do yourself, if you forego the PCH.