AMD Zen 4 & Socket AM5 Explained: PCIe Lanes, Chipsets, Connectivity

[kapqa]

Some boards will have USB4 i guess (has been announced already) ; if the CPU are great, prices fair, then there is nothing much to complain about.

 

[TheinsanegamerN]

What? CPUs are aging more than ever

LOLWAT? Somebody doesnt remember the netburst era, or the GHz race, or really any time between 1997 and 2011. A 10 year old PC can run modern software perfectly fine. in 2010 nobody called a 2000 era PC anything but scrap iron.

now that Intel and AMD feel like competing again for a change

Software still runs perfectly fine on aging hardware. unless you are chasing high refresh rates sandy bridge with an OC can still (just) maintain 60 FPS minimum in most games. Haswell is still perfectly fine for gaming and any consumer task. If all you do is browse even core 2 era hardware works fine.

And new software, frankly, is not making significant strides towards needing uberpowerful CPUs outside of the content production industry.

and ARM is threathning to steal their lunch.

2013 wants its talking point back. Maybe by 2050 we'll finally see ARM desktops commonplace!

That's a very good point but I believe general consumer market would be loud enough that they wouldn't risk it.

What I could see coming is AMD being a lot more careful with what they promise to not repeat what happen when they launched zen3 (at first they wanted to support only x570/b550 and were quickly "forced" to support b450/x470 as well, and through market competition now even b350/x370 is supported as was always promised). But then again, companies are always repeating the same mistakes over and over again so who knows

They didnt thinkt he consoomers would worry that much about either rDNA or AM4, if you think they've learned their lesson I have a bridge to sell you.

 

[Daven]

X670 is 2x B650 if it wasn't clear. No chipset at all is currently not an option.

Two ports appear to the the norm, as both ASMedia and Intel supports two ports in their chipsets.

Crap, you are right. It’s gonna take me some time to remember what has 1 and 2 packages. So its basically…
X670E - 2 packages - ATX
X670 - 2 packages - ATX
B650E - 1 package - ATX/mITX (conjecture)
B650 - 1 package - ATX/mITX
A6XX - chipset less - mITX (conjecture)

I don’t believe we will see many microATX so I left it out.

 

[FeelinFroggy]

I plan on upgrading my platform this year and I think I may have picked a great time to upgrade. I expect AMD and Intel to put out some very nice processors later in the year and I plan on getting one of them.

Ain't competition great!

 

[Assimilator]

Please show me where Alder lake has USB4 or Thunderbolt 4 built in on the block diagram below. Only Intel's mobile parts have native support and AMD does support USB4 on the 6000-series mobile chips.

That's very odd... I didn't realise that ADL doesn't have native TB4/USB4, I assumed it does because TGL does, but you're right, it appears they cut that feature. Hopefully it will make an appearance on desktop with RKL.

And no, not all USB4 ports have to support DP Alt Mode, the requirement is only for one display output, whereas Thunderbolt has to support two, both standards call for 4K output.

https://en.wikipedia.org/wiki/USB4#Support_of_data_transfer_modes states (based on the USB-IF spec) that DP alt mode support is required for USB4 hosts and hubs.

No, four is the limit, so it's either an HDMI, DP or DVI port, or USB-C DP Alt mode. So far, no motherboard seems to support more than one USB-C DP Alt mode output in combination with USB 3.2 support. Expect some of the USB4 and Thunderbolt 4 equipped boards to have two USB-C ports that can handle display output as well.

TY!

ASRock seem to prefer eight SATA ports...

ASRock has always had a hardon for those, I don't understand why.

 

[Mussels]

"Three of the USB 3.2 ports also support DP Alt Mode, something we've seen several announced boards supporting on at least one USB-C port."
This.


Oh yes, gimme dat USB-C output!

Who cares about space-wasting honking huge connectors for our IGP's when our USB-C outputs can cheaply and easily used with displayport connections?

CPU

So I was right - no native USB4 from this platform. That is seriously disappointing considering Tiger and Alder Lake has it baked in. The biggest benefit of USB4 (apart from bandwidth) is that there's none of the "does this USB-C port support DP alt mode" nonsense, because all USB4 ports have to support DP alt mode.

... and there we have it, up to four USB 3.2 gen 2 ports, but DP alt mode is optional and one of them arbitrarily doesn't support DP alt mode at all. WHHHHHYYYYYY? It also seems like these ports cannot be bonded to 3.2 gen 2x2, again why?

Are the up-to-4 display outputs muxed with the up-to-3 USB 3.2 gen 2s with DP alt mode? In other word, could you have 7 displays being driven by the CPU, or is 4 the hard limit?

Chipset

I like the option to have zero SATA ports in favour of an extra NVMe drive, even if it's only PCIe 3.0.

The daisy-chained chipsets are a terrible kludge that will be a nightmare in terms of latency for devices hanging off the most downstream one. Also, what happens if one of the chipsets fails? Does the other continue to work and the board behaves like a B650? Or is it just a dead board?

Why can only the first two 3.2 gen 2 ports be bonded to 3.2 gen 2x2?

Platform overall

I honestly don't understand why AMD is launching a platform that is not natively USB4-capable... if I was wearing my conspiracy theorist hat I'd say it's to allow ASMedia to sell USB4 chips separately and thus make more money. Considering Intel has had platform-native USB4 since Tiger Lake in 2020, this makes the AM5 platform look dated before it's even launched. The chipsets' low PCIe lane count (not bandwidth) compared to ADL, is a further concern.

As such, AM5 is of no interest to me right now. I was already planning to stay on AM4 until Zen 4's successor arrived with all the bugs fixed, but native USB4 was the variable that had the potential to sway me... no native USB4, no reason to upgrade.


But there likely aren't going to be many mATX/ITX X670/X670E boards, which is a slap in the face to the SFF crowd who want to build high-end systems in small spaces.

I do agree it's weird the laptops from both sides have this while the desktops dont

Cost - they can bring all this in with X770, whilst launching AM5 at a cheaper price point.
Unlike intels side of things, AMD is planning for these boards and CPU's to be inter-compatible for several years: So these first gen boards need to cut the most expensive, least likely to be used peripheral options to lower the platform cost and save something for the definitely coming second generation chipsets.

At a guess the 700 series chipsets will be gen 5, with native USB 4 - clear and simple marketing and distinction for end users, stick with 600 series for cheaper builds and 700 series for the high end connectivity users

I too want native USB 4 (one of the few things that i would upgrade for, although i could just do a PCI-E card)



On the PCI-E lanes... while i see this as unlikely, we did see lane variance on AM4.
I wonder if they left the potential for more lanes in future chipsets, or if they plan on doing 5.0 -> twice as many 4.0

 

[Minus Infinity]

Software still runs perfectly fine on aging hardware. unless you are chasing high refresh rates sandy bridge with an OC can still (just) maintain 60 FPS minimum in most games. Haswell is still perfectly fine for gaming and any consumer task. If all you do is browse even core 2 era hardware works fine.

You clearly don't do photo or video editing. My 2012 Ivy Bridge CPU ran like shit by around 2016 on Adobe LR and PS. Editing became a chore and jumping to Zen 1 made a massive difference and Zen 3 is much faster than that for what I do. Also other software might run on old CPU's but they don't run it fast. I had Matlab sims that were glacial on Ivy Bridge that fly on Zen 3.

 

[TheLostSwede]

https://en.wikipedia.org/wiki/USB4#Support_of_data_transfer_modes states (based on the USB-IF spec) that DP alt mode support is required for USB4 hosts and hubs..

I don't see where my statement disagrees with that. One port is required per host controller, more is allowed. Most will likely do two. Hubs are somewhat more complicated now and also requires PCIe support, which oddly enough the host controllers don't.

 

[stimpy88]

Lifespan of "platform", yes, "chipset", no.

You can't change the socket, and that is the limiting factor here. I could not care less if the chipset supports 1024 lanes of PCIE5, as at the end of the day, it has to be squeezed into just 4 to get back to the CPU.

 

[Bomby569]

As someone that doesn't go for the high end, i can't agree more with Brian. AMD changed a lot, GPU's and CPU's for the worst in this last year.

 

[Dr_b_]

Going to wait on this AM5, concerned about the dual chipsets. AMD should really bring chipset development in house, and take it more seriously.

Waited 2 years for AM4 but still had lots of problems, was impacted by system freezes (solved by agesa update eventually, but it took a year, set the system aside and built and used an intel x299 instead because system freezes are unacceptable), was impacted by USB drop outs (just now fully solved by Agesa update this past month), still having other minor issues but they are mostly ignorable. Really want more PCIe slots. Slots. M.2 uses up a lot of lanes from chipset, but its not flexible, whereas a slot you can put in a m.2 in via a card, or any other device.

 

[R0H1T]

I think generally speaking ASmedia have done a "relatively" good with prior gen so going with them isn't an issue. This also frees up valuable time/resources at AMD which could be used to better their (x86) uarch or GPU's as such.

 

[Assimilator]

Really want more PCIe slots. Slots. M.2 uses up a lot of lanes from chipset, but its not flexible, whereas a slot you can put in a m.2 in via a card, or any other device.

And what exactly are you going to use those slots for? The whole reason that M.2 slots are on the motherboard instead of discrete add-in cards is cost, flexibility isn't free. For example the only real option (ASUS Hyper M.2) is the cost of an entry-level motherboard.

 

[trsttte]

And what exactly are you going to use those slots for? The whole reason that M.2 slots are on the motherboard instead of discrete add-in cards is cost, flexibility isn't free. For example the only real option (ASUS Hyper M.2) is the cost of an entry-level motherboard.

The asus hyper m.2 is different than a simple 4x adaptor that doesn't even need power, those go for 10$. M.2 also requires extra keepout areas and holes in the board while a slot can be simpler to place.

With 2x m.2 coming from the CPU I really don't need any more coming from the chipset and even if I do I'd prefer the flexibily of simple generic slots. I think a lot of these supposed "features" like extra m.2 with "heatsinks" (aka a chunck of painted metal) are just ways to upcharge the boards

 

[tussinman]

What? CPUs are aging more than ever now that Intel and AMD feel like competing again for a change and ARM is threathning to steal their lunch. Absolutely keep whatever works for as long as possible but CPUs are definetely aging.

He said not aging as bad which is true. Mid 90s to maybe early 2010s the gaps for consumer needs/demands where alot more apparent

LOLWAT? Somebody doesnt remember the netburst era, or the GHz race, or really any time between 1997 and 2011. A 10 year old PC can run modern software perfectly fine. in 2010 nobody called a 2000 era PC anything but scrap iron.

True. My 3770k is over 10 years old and it does 90% of my programs/task with zero issues. It's actually capable of accomplishing consumer level task. Like you said take a 2000 era computer and run try to run Windows 7 on it, nothing but scrap metal.

You clearly don't do photo or video editing. My 2012 Ivy Bridge CPU ran like shit by around 2016 on Adobe LR and PS. Editing became a chore and jumping to Zen 1 made a massive difference and Zen 3 is much faster than that for what I do. Also other software might run on old CPU's but they don't run it fast. I had Matlab sims that were glacial on Ivy Bridge that fly on Zen 3.

It was pretty obvious that he was speaking in general terms. A 10 year old CPU present day still has some use/worth. Obviously higher end and more niche uses no (to be fair in 2012 the Xeons where the CPUs that where actually targeted towards your usage) but it still can be used for most consumer level task

The original quote he quoted was how CPU's are aging more now then ever which is actually the complete opposite (try and run windows vista era programs/games on a 1997 cpu and try to run windows windows 7 era games/programs on a 1999 era computer and then claim "CPU's are aging worst now")

 

[TheLostSwede]

Going to wait on this AM5, concerned about the dual chipsets. AMD should really bring chipset development in house, and take it more seriously.

Sorry, but first of all why? And secondly, what's wrong with this chipset?
I'm honestly interested in getting your technical evaluation of it, since you clearly know something AMD doesn't even know.

Waited 2 years for AM4 but still had lots of problems, was impacted by system freezes (solved by agesa update eventually, but it took a year, set the system aside and built and used an intel x299 instead because system freezes are unacceptable), was impacted by USB drop outs (just now fully solved by Agesa update this past month), still having other minor issues but they are mostly ignorable. Really want more PCIe slots. Slots. M.2 uses up a lot of lanes from chipset, but its not flexible, whereas a slot you can put in a m.2 in via a card, or any other device.

The system freezes only affected a minority of users from my understanding, it's one issue I didn't have. The USB dropout was fixed much longer back than that, unless it was specific to your board/maker.
The PCIe/M.2 layout it up to the board makers, take it up with them, it's not AMD that's imposing limitations here.

 

[Flaky]

I agree, but I was actually at the show floor of Computex, handled boards and talked to people. ASMedia doesn't seem to be ready for PCIe 5.0 and I also asked why it wasn't a chipset per CPU interface, but was told that AMD had decided to go for daisy chaining.

Thanks for clarifying.

Hence the somewhat awkward diagrams here, following Intel's HSIO layout to a degree, as it makes it easier to explain muxed interfaces.

Nothing awkward here - such diagrams are the best way to present I/O capabilities, thank you for them Makes it clear what to expect on boards and verify on which designs manufacturers actually put some effort.

One thing that keeps me wondering is how they will de-feature A620 platform. With only one x4 chipset downlink disabled there would still be a lot of I/O in play... So much that most consumers wouldn't really need to jump into B650 territory. There probably will be more cuts to convince people. USB3 2x2 unavailable? One CPU x4 link disabled, Intel H510/H610 style?

A6XX - chipset less - mITX (conjecture)

With AM4 providing almost zero chipsetless boards, AM5 has even less chance to make it common.
AM4 at least did have a built-in storage controller with two lanes configurable as SATA or PCIe.
No AM5 leak even mentions cpu-attached SATA, and that's a big no-no for consumer-oriented board. External controllers are always an option, but combined costs would make simply going for A620 more reasonable.

 

[Wirko]

I also asked why it wasn't a chipset per CPU interface, but was told that AMD had decided to go for daisy chaining.

This can change during the life of the AM5 socket. Those are all just PCIe 5 links, after all, and Ryzens after 7000 could become more flexible in this regard.

 

[TheLostSwede]

This can change during the life of the AM5 socket. Those are all just PCIe 5 links, after all, and Ryzens after 7000 could become more flexible in this regard.

Possibly yes. We obviously don't have any insight into what AMD is planning for the next generation of hardware, but I can see PCIe 5.0 chipset connectivity being part of X770 or whatever chipset the next generation of AM5 boards will have.

 

[trsttte]

This can change during the life of the AM5 socket. Those are all just PCIe 5 links, after all, and Ryzens after 7000 could become more flexible in this regard.

That looks like a good excuse to break compatibility in the future with a "new" sAM5 socket similar to what happened with sTRX40

Remind me in 1 to 2 years I guess

 

[chrcoluk]

It would be amazing if the 2 extra x4 general purpose lanes were routed to pcie slots, imagine a board where all or almost all of its pcie slots were cpu routed.

I expect instead they will be inefficiently used on m.2 slots. Companies like ASRock who are the king of i/o options should at least have optional routing to PCIE slots shared with the m.2 slots I hope like on my b450 pro 4. Good to see they will still offer 8 ports as well albeit only on what will probably be really pricey boards.

Also why does the chipset still only have 4 lanes?

I assume pcie gen 3 will be dead on this gen, so cheaper gen 3 boards will be history. Have they figured out a way to make gen 4/5 boards with same number of PCB layers as gen 3 yet?

As someone that doesn't go for the high end, i can't agree more with Brian. AMD changed a lot, GPU's and CPU's for the worst in this last year.

On the basic point he has nailed it, in short becoming an industry for people who love the newest tech, but the budget side of things has gone to crap.

There should be a budget option on AM5 option for gen 3 PCIE, DDR4, using existing ATX standards and not having VRM's over spec'd. 90% of people would be satisfied with that.

I screen grabbed this.

And what exactly are you going to use those slots for? The whole reason that M.2 slots are on the motherboard instead of discrete add-in cards is cost, flexibility isn't free. For example the only real option (ASUS Hyper M.2) is the cost of an entry-level motherboard.

Not sure why you disagree with him.

Flexibility is king and should be the fore front of board design. Or should we all comply and be stuffing our machines with m.2 drives?

I can answer your question of the uses.

1 - Easy install NVME drives, onboard slots are fiddly and hard to cool.
2 - Discrete sound.
3 - Capture card.
4 - I/O card whether its SATA, SAS, NVME or other.
5 - Wifi/Ethernet card.
6 - USB expandability.
7 - Additional GPUs e.g. for virtualization.

Also there is no evidence M.2 slots are cheaper than PCIE slots for manufacturing. Cheaper boards tend to have a higher PCIE slot to M.2 ratio which if anything suggests the opposite. ASUS themselves are always over priced, I brought a PCIE M.2 adaptor for £8 although is now £12.

https://www.amazon.co.uk/gp/product/B084GDY2PW/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

4 slots?

https://www.amazon.co.uk/4-Port-Controller-Expansion-Adapter-Converter-4-Port-PH44/dp/B09CTZ8QJM/ref=pd_lpo_1?pd_rd_i=B09CTZ8QJM&th=1

I have sat wondering what has led to the manufacturers making these decisions, I think part of the problem is they are too heavily influenced by the review industry, reviewers seem to be backing the trend of a new system design that promotes heavy use of M.2, and just a single GPU installed with no other PCIE devices. Normal consumers dont have access to media departments and designers.

 

[trsttte]

It would be amazing if the 2 extra x4 general purpose lanes were routed to pcie slots, imagine a board where all or almost all of its pcie slots were cpu routed.

I expect instead they will be inefficiently used on m.2 slots. Companies like ASRock who are the king of i/o options should at least have optional routing to PCIE slots shared with the m.2 slots I hope like on my b450 pro 4. Good to see they will still offer 8 ports as well albeit only on what will probably be really pricey boards.

Also why does the chipset still only have 4 lanes?

I assume pcie gen 3 will be dead on this gen, so cheaper gen 3 boards will be history. Have they figured out a way to make gen 4/5 boards with same number of PCB layers as gen 3 yet?


On the basic point he has nailed it, in short becoming an industry for people who love the newest tech, but the budget side of things has gone to crap.

There should be a budget option on AM5 option for gen 3 PCIE, DDR4, using existing ATX standards and not having VRM's over spec'd. 90% of people would be satisfied with that.

I screen grabbed this.

View attachment 249678


Not sure why you disagree with him.

Flexibility is king and should be the fore front of board design. Or should we all comply and be stuffing our machines with m.2 drives?

I can answer your question of the uses.

1 - Easy install NVME drives, onboard slots are fiddly and hard to cool.
2 - Discrete sound.
3 - Capture card.
4 - I/O card whether its SATA, SAS, NVME or other.
5 - Wifi/Ethernet card.
6 - USB expandability.
7 - Additional GPUs e.g. for virtualization.

Also there is no evidence M.2 slots are cheaper than PCIE slots for manufacturing. Cheaper boards tend to have a higher PCIE slot to M.2 ratio which if anything suggests the opposite. ASUS themselves are always over priced, I brought a PCIE M.2 adaptor for £8 although is now £12.

https://www.amazon.co.uk/gp/product/B084GDY2PW/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

4 slots?

https://www.amazon.co.uk/4-Port-Controller-Expansion-Adapter-Converter-4-Port-PH44/dp/B09CTZ8QJM/ref=pd_lpo_1?pd_rd_i=B09CTZ8QJM&th=1

I have sat wondering what has led to the manufacturers making these decisions, I think part of the problem is they are too heavily influenced by the review industry, reviewers seem to be backing the trend of a new system design that promotes heavy use of M.2, and just a single GPU installed with no other PCIE devices. Thelostswede who I think attended this event and has spoken to some rep's there does he have this point of view which he shared with those reps? It might share some light as to the direction the industry is going in.

That Asrock solution is pretty neat but AMD is pushing for mandatory gen5 on the m.2 slot on both x670 and b650 to offer an incentive for storage vendors to also bring those solutions to market quickly. The advantages are not really visibly right now but I think the hope is with direct storage they'll be able to offer some major performance advantage quite soon.

To the cost point, Moore's Law Is Dead is reporting that 2 X670 chipsets are cheaper than a single X570, if true that already goes some way towards absorving the price increase from moving to pcie gen5 and extra layer pcbs.

The argument of "what gamer needs pcie gen5" is also completely flawed, you could also say "what gamer needs a new gen system when the last gen is selling at a discount" or the classic "what gamer needs more than 4 cores". Software that makes use of higher speeds/performance will be available as higher speeds/performance becomes available, not the other way around. Granted we haven't really scratched the surface of what gen4 nvme is able to do because it was also a short lived spec, but that doesn't mean we can't continue to move forward on the hardware side while the software catches up.

 

[Wirko]

Have they figured out a way to make gen 4/5 boards with same number of PCB layers as gen 3 yet?

How many layers does DDR5 require? And other things, like the quality of insulator between layers? If the requirements for PCB for DDR5 are as strict as they are for PCIe 5 then the latter can't increase the price much.

 

[TheLostSwede]

It would be amazing if the 2 extra x4 general purpose lanes were routed to pcie slots, imagine a board where all or almost all of its pcie slots were cpu routed.

I expect instead they will be inefficiently used on m.2 slots. Companies like ASRock who are the king of i/o options should at least have optional routing to PCIE slots shared with the m.2 slots I hope like on my b450 pro 4. Good to see they will still offer 8 ports as well albeit only on what will probably be really pricey boards.

Also why does the chipset still only have 4 lanes?

I assume pcie gen 3 will be dead on this gen, so cheaper gen 3 boards will be history. Have they figured out a way to make gen 4/5 boards with same number of PCB layers as gen 3 yet?


On the basic point he has nailed it, in short becoming an industry for people who love the newest tech, but the budget side of things has gone to crap.

There should be a budget option on AM5 option for gen 3 PCIE, DDR4, using existing ATX standards and not having VRM's over spec'd. 90% of people would be satisfied with that.

I screen grabbed this.

View attachment 249678


Not sure why you disagree with him.

Flexibility is king and should be the fore front of board design. Or should we all comply and be stuffing our machines with m.2 drives?

I can answer your question of the uses.

1 - Easy install NVME drives, onboard slots are fiddly and hard to cool.
2 - Discrete sound.
3 - Capture card.
4 - I/O card whether its SATA, SAS, NVME or other.
5 - Wifi/Ethernet card.
6 - USB expandability.
7 - Additional GPUs e.g. for virtualization.

Also there is no evidence M.2 slots are cheaper than PCIE slots for manufacturing. Cheaper boards tend to have a higher PCIE slot to M.2 ratio which if anything suggests the opposite. ASUS themselves are always over priced, I brought a PCIE M.2 adaptor for £8 although is now £12.

https://www.amazon.co.uk/gp/product/B084GDY2PW/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1

4 slots?

https://www.amazon.co.uk/4-Port-Controller-Expansion-Adapter-Converter-4-Port-PH44/dp/B09CTZ8QJM/ref=pd_lpo_1?pd_rd_i=B09CTZ8QJM&th=1

I have sat wondering what has led to the manufacturers making these decisions, I think part of the problem is they are too heavily influenced by the review industry, reviewers seem to be backing the trend of a new system design that promotes heavy use of M.2, and just a single GPU installed with no other PCIE devices. Normal consumers dont have access to media departments and designers.

Based on your comments here, did you even read and understand my article?

How many layers does DDR5 require? And other things, like the quality of insulator between layers? If the requirements for PCB for DDR5 are as strict as they are for PCIe 5 then the latter can't increase the price much.

Six it seems, as only DDR4 Intel boards use four layer PCBs from what I've seen. PCIe 5.0 seems to require eight if there's a x16 slot, but can do six if it's only for the M.2.

 

[andry360]

Is it really necessary to give consumer boards 16x lanes of PCI 5.0?
I thought that video cards doesn't even use full 16x 4.0 lanes.

This thought came in my mind thinking that maybe they could use the spare lanes for other purpose. Or maybe couldnt' they check if the device connected has 8 or 16 lanes and dedicate the spare lanes for other connections?

I clearly am talking from a point of view of a ignorant in this matter