Discussion AMD confirms ZEN 3 4'th GEN Ryzen Desktop CPUs will only support the new AMD 500-series (or later) chipsets.

[Deleted member 2731765]

Hello all,

Just wanted to share this news with you guys.

TechPowerUp has just posted a very interesting article. I will try to keep this short and simple though. According to TPU's article it looks like AMD's next-gen ZEN3 CPUs won't be backwards-compatible with the older 400-series, as well as the 300-series of Motherboard chipsets.

This is a bummer, since older Motherboards won't be compatible with the new upcoming ZEN 3 4000 series of processors, which provides very little room for upgrade. The 4'th Gen ZEN 3 processors will only work on the AMD 500-series (or later) chipsets, the X570 and B550 Motherboards.

Owners of the existing 500-series motherboards will have to update their motherboard's BIOS to enable support for these new Ryzen 4000 processors. Honestly speaking, I'm a bit shocked with this move from AMD. I was hoping the company will support older Gen Motherboards, giving 'backwards compatibility' to end users in the process as well. But it seems this is not the case.

Those gamers who bought premium 'X470' motherboard chipsets for example were actually hoping for a compatibility with the next-gen upcoming ZEN CPUs as well, but now it seems they won't be able to use these processors, should they plan to upgrade. As of now, only the B550 chipset is available, but expect more high-end chipsets when the launch dates come closer. The AMD B550 is a new mid-range chipset by AMD.

According to TPU's article, B550 is a low-power silicon chipset, having similar 5-7 W TDP as the older 400-series chipset, and it's likely that the chipset is from ASMedia.

The AMD B550 chipset currently only supports the 3rd generation Ryzen "Matisse" processors. Older Ryzen 2000 series CPUs, first gen Ryzen 1000 processors are not supported. The same applies for Athlon 200, "Picasso" APUs, and the Ryzen 3000G series (with integrated Radeon VEGA graphics).

According to AMD, the company says that it ran into some ROM size limitations, when trying to push the AGESA microcode for all the older CPUs. As per AMD, the flash memory chips that store the BIOS have capacity limitations, and not all AM4-based motherboards feature dual-BIOS chip design (mostly found on the more expensive and high-end boards). Good news is that the chipset will support the upcoming "ZEN 3" microarchitecture CPUs.

The Ryzen 4000 series family would be the last generation of processors to support the AM4 socket because with Ryzen 5000 series, ZEN4 architecture will be used which will require a new socket as well as a new chipset.

So there you have it. This seems to be a strange move made by AMD in my opinion. I was hoping for more longevity of the AM4 platform though. More details on this news can be found here.

 

[Deleted member 2731765]

I find this article very interesting. It's an old review, but worth checking out.

AMD Ryzen 9 3900X Tested on Cheap B350 Motherboard !!

AMD Ryzen 9 3900X Tested on Cheap B350 Motherboard

We're testing AMD's 12-core, 24-thread Ryzen 9 3900X flagship on a cheap B350 motherboard. Performance results are good, even overclocking works as well as on X570. Special attention is paid to VRM temperatures, which we measure using a FLIR thermal camera.

www.techpowerup.com

 

[NightHawkRMX]

Amd also said 300 series wouldnt work with zen 2. But most do.

 

[drea.drechsler]

Amd also said 300 series wouldnt work with zen 2. But most do.

Because a) AMD didn't lock it out in AGESA and b) motherboard mfgr's decided to go ahead and provide a BIOS with 300 series beta AGESA in it for most boards. But not all b350 boards got one, even so.

There's no assurances they will do the same for 400 series boards. There is a lot of financial incentive for board mfr's to not do it if Zen3 proves to be another killer update.

 

[InvalidError]

There is a lot of financial incentive for board mfr's to not do it if Zen3 proves to be another killer update.

There is incentive for motherboard manufacturers and AMD to break backward compatibility regardless of how good Zen 3 might be: it reduces everyone's backwards QA and tech support costs. AMD may be thinking that committing to a socket for four years (possibly five if there is a Zen 3+) was a mistake.

 

[Karadjgne]

Principles of economics say that first you hook the impulse buyers. Right before that well dries up, you grab the masses. So what you'll probably see is everyone starting out the same as the X570's did, with no APU support, tailoring to the impulse sales and consequent gpu sales hike, but then introducing an 'update' or a 'Uber MAX' version which will have 4000 series compatability grabbing everyone else who wants the new cpus and prolonging sales levels after the initial rush.

AMD did that with a lot of the AM3/+ mobo's, initially only 95w, but magically later, a 125w updated bios for the FX83's

 

[drea.drechsler]

And what's not been mentioned is how this might impact market up-take of the new Zen 3 processors since they won't work on 400 series motherboards.

So the scenario I see now is users who're currently happy with a 2700X on their 400 series motherboards and holding for a leapfrog gain over Zen2 are going to have to eat the whole hog with (effectively) full-system upgrades. That must end up dealing a serious blow to buyer eagerness when they come to realize it at release time. I feel they would have been the eager-ist of early adopters at release of Zen3, ready-made market demand at release that just got blown off.

Now the eagerist of early adopters are probably going to be more Intel converts and maybe some Zen1 upgraders who've been hanging on with a 300 series board and see their (by then) nearly 4 YO system as ready for renewal. But either way it's a much smaller crowd lining up for the new processor.

Maybe AMD can do this because they feel Zen3 is going to offer such an improvement over even Zen2 that it will compel upgrading even if it means a new system. Or maybe even enough of an improvement that the most diehard of Intel fanboys may be too embarrassed to compare FPS benches anymore...thereby encouraging the rest that it's definitely time to leave the fold.

Or maybe AMD's increasing seeing the limits of 7nm wafers they can get from TSMC as constraining, so slower sales growth even in the face of a new arch release won't really bother them. At least in the consumer market space as they must increasingly focus on the rich opportunities laying before them in the data center market space.

 

[InvalidError]

Or maybe AMD's increasing seeing the limits of the 7nm wafers they can get from TSMC as constraining them so slower sales growth, even in the face of a new arch release, won't really bother them.

More likely, AMD looked at the total cost of supporting backward compatibility and concluded that the savings in R&D, QA, RMA, etc. costs outweigh lost sales.

 

[Third-Eye]

I still think there is a good chance we will see Ryzen 4000 on at least 400 Series motherboards 3-6 months after release. If Ryzen 4000 is going to be the last of the AM4 CPUs, I think fewer people will be inclind to both upgraded their boards to 500 series and get Ryzen 4000. I can see a large portion of the potential customers still using Ryzen 1000/2000, waiting even longer for Ryzen 5000 or Intel desktop 10nm CPUs when they will have to upgrade everything anyway, but have the new option of faster DDR5 ram.

 

[drea.drechsler]

More likely, AMD looked at the total cost of supporting backward compatibility and concluded that the savings in R&D, QA, RMA, etc. costs outweigh lost sales.

I'm sure that they figure into the equation, but I do tend to doubt that those costs are a significant driver in the analysis. Especially since the chipsets themselves are so similar function-wise. And lastly, the nature of business is you incur cost in order to build sales and blowing off a ready made market merely inhibits your ability to do. So I have to think they would have another reason than that.

I would agree the motherboard mfr's might have that concern though. AGESA and SMU microcoding is very much configurable and, as I understand it, they have a much tougher job 'fitting' the AGESA to each of their boards. They're not going to build sales for the new and probably higher margin 500 series motherboards by doing it.

 

[drea.drechsler]

I still think there is a good chance we will see Ryzen 4000 on at least 400 Series motherboards 3-6 months after release. If Ryzen 4000 is going to be the last of the AM4 CPUs,
...

In my case, I'm afraid I won't if they do. I think MSI will update their MAX boards only as trying to squeeze their code down to fit my non-MAX Mortar would be too much.

...
If Ryzen 4000 is going to be the last of the AM4 CPUs, I think fewer people will be inclind to both upgraded their boards to 500 series and get Ryzen 4000. I can see a large portion of the potential customers still using Ryzen 1000/2000, waiting even longer for Ryzen 5000 or Intel desktop 10nm CPUs when they will have to upgrade everything anyway, but have the new option of faster DDR5 ram.

I definitely see how that figures even more into a dis-incentive to upgrade to Ryzen 4000 for many. So again, either AMD's absolutely confident they got a killer in Zen3 that will finally compel even the most diehard Intel fans to cross (huge numbers there...huge), or they're content with slower market uptake for some reason. And the best reason I can imagine is they are so focused on 7nm in the data center that slower growth in desktop is acceptable when they have finite constraints on the wafers they can get from TSMC.

 

[Karadjgne]

I've seen a lot of assumption about 4k series all being the same. With the difference in VRM sizes between X570's and B450, the B550 is going to be limited. They'll be somewhere in between. So the 4950x will require less than 80/90A, to fit on a X570, but that also means the low end cpus like the 4600 or 4300x won't be the 105w monsters either, they'll be 65w class cpus, roughly. Since the B550 is slated to use Gen3 pcie, which is the max capable on a B450, everything fits except for bios recognition. There might be certain board excluded due to VRM amperage size, but I can't see any definitive reason why an MSI MAX B450 couldn't house a 4600.

 

[InvalidError]

I'm sure that they figure into the equation, but I do tend to doubt that those costs are a significant driver in the analysis.

Pretty sure you are grossly under-estimating the effort required here. Characterizing old boards and feeding the results to CPU design team to take into account specifically for backward compatibility reasons is thousands of man-hours for largely hypothetical revenue: the people who would only upgrade if they had a drop-in path. I bet those account for less than 1% of the market.

 

[drea.drechsler]

Pretty sure you are grossly under-estimating the effort required here. Characterizing old boards and feeding the results to CPU design team to take into account specifically for backward compatibility reasons is thousands of man-hours for largely hypothetical revenue: the people who would only upgrade if they had a drop-in path. I bet those account for less than 1% of the market.

Pretty sure I'm not.

You're confusing the job the mobo mfr's would do with AMD. All AMD has to do is make the AGESA compatible with the chipset in one reference design, both of which are probably fairly standard with well understood deviation since 300 series...and X570. Motherboard mfr has to account for their designs, to the extent they deviate from reference. AGESA has a lot of handles and knobs to do that, we see so very few exposed in our BIOS'. And if implemented in 300/400 series boards the most difficult part is simply ruled out...no PCIe 4 from CPU to anything, only PCIe 3 or 2.

And lastly, even if if the 'drop in' upgraders really are only 1% that's quite a few. And they are the most important customers AMD has. They're the enthusiast AMD customers, earliest of early adopters. The ones leading the way, figuring out the problems and showing others how to do it with a positive attitude. And even more importantly: posting benchmarks all over and loudly showing how good the product is. They do what the Intel-centric popular press won't: they tell the true story of how it performs in real-world use cases. Never under estimate the importance of that market to AMD.

 

[InvalidError]

Motherboard mfr has to account for their designs, to the extent they deviate from reference. AGESA has a lot of handles and knobs to do that, we see so very few exposed in our BIOS'.

The more backward compatibility you want to maintain with substantially modified CPU, the more extra knobs you need to make it work. Motherboard manufacturers cannot turn knobs that AMD did not put in silicon and for AMD to know what knobs to add to help backward compatibility, it needs to sample boards and characterize them.

 

[drea.drechsler]

The more backward compatibility you want to maintain with substantially modified CPU, the more extra knobs you need to make it work. Motherboard manufacturers cannot turn knobs that AMD did not put in silicon and for AMD to know what knobs to add to help backward compatibility, it needs to sample boards and characterize them.

First: have you ever worked in design? The product mfr does not deviate their specs from reference for anyone...that means no knobs the reference doesn't need, not without a custom design contract. The board mfr. assumes total liability and responsibility to make it work when they deviate design from reference. They have a lot of discussions with Industry before they settle on the reference, but once it's settled it's done. If they didn't the design would never be done.

If we saw that scenario (custom designs) I have to think we'd see different AGESA versions/subversions throughout the various boards. And TheStilt couldn't transplant SMU's will-nilly into hacked BIOS's for 400 series boards as he did when they were so slow implementing 1003ABBA. All except Asrock's...and why? because they deviated from reference so far he couldn't make sense of it.

So, that aside where I agree is the motherboard mfr's doubtless see greater risk. But also gives me reason to doubt we'll see them doing the same thing for 400 series boards as they did for 300 series board and Ryzen 3000. And also, that AMD doesn't (or can't) force them to is telling. I don't think it's over dramatizing things to say AMD's corporate survival was at stake before so maybe they sees things differently now.

 

[Third-Eye]

I wouldn't mind if they dropped all support for everything Zen/Zen+ and only support Zen 2 for backward compatibility with 400 series chipsets. In my opinion, it's a bit unreasonable for people think they should have support for Ryzen 4000 on older 300 series chipsets. Support for Zen 2 was already a little dicey on 300 series boards.

 

[InvalidError]

First: have you ever worked in design? The product mfr does not deviate their specs from reference for anyone...that means no knobs the reference doesn't need

AMD completely changed the CPU packaging and substrate structure with Zen 2 and chiplets. The onus for maintaining backwards electrical compatibility with sockets and providing motherboard manufacturers whatever additional knobs they may require to make the drastic changes in CPU characteristics rests almost entirely on AMD since it is AMD who changed their side of the design and board manufacturers cannot change existing boards beyond firmware updates.

Based on what happened on TR4 and AMD having to add seven layers to the CPU substrate to make Zen 2 work on AM4, AM4 may have come close to being end-of-life with Zen+.

 

[drea.drechsler]

AMD completely changed the CPU packaging and substrate structure with Zen 2 and chiplets. The onus for maintaining backwards electrical compatibility with sockets and providing motherboard manufacturers whatever additional knobs they may require to make the drastic changes in CPU characteristics rests almost entirely on AMD since it is AMD who changed their side of the design and board manufacturers cannot change existing boards beyond firmware updates.

Based on what happened on TR4 and AMD having to add seven layers to the CPU substrate to make Zen 2 work on AM4, AM4 may have come close to being end-of-life with Zen+.

Makes a good case for not bringing out Vermeer on AM4 at all. No reason not to have an X570 as well as B550 in both AM4 and AM5....or maybe AM4+ if you must. Or if the confusion might be too much, X575 and B555 or whatever.

As has been noted often and long, they only promised 'support' for AM4 TO 2020, not through. And SUPPORT doesn't have to mean new architecture processor releases. We've seen several new processors for AM4 (3100/3300 most recently) in 2020. Even back at it's realease last year I think most people were assuming AM4 would end at Matisse anyway. It would make the whole thing a lot more palatable I think.

 

[Deleted member 2731765]

This topic has just reached 1K views ! LOL....

 

[drea.drechsler]

This topic has just reached 1K views ! LOL....

Check out /r/amd on Reddit....MULTIPLE threads beating on this issue. Even Steve at GN has jumped in to have his say on it.

ONLY 1K views...and not a dozen threads here. This is a very laid back forum, I do have to say.

 

[Deleted member 2731765]

Check out /r/amd on Reddit....MULTIPLE threads beating on this issue. Even Steve at GN has jumped in to have his say on it.

ONLY 1K views...and not a dozen threads here. This is a very laid back forum, I do have to say.

Wow ! Btw, having more threads isn't necessary. Quality is more important than quantity, in my opinion. This is mostly a TECH forum, and less of a "discussion" or a chat hub.

I mean people mostly use these Forums to get help with troubleshooting their problem, which is PC and "hardware" related. I've not seen too many general discussion threads though.