Update: On May 19, 2020, AMD announced that they will be supporting Zen 3 processors in B450 and X470 motherboards. They are still working out the details, but they will work with the motherboard vendors to make this happen. This is good news for people who bought B450 and X470 motherboards.
On May 7, 2020, AMD broke the news that their upcoming Zen 3 desktop processors will only be supported on 500 series chipsets (meaning X570 and B550). Before this announcement, the fairly widespread assumption in the technical community was that Zen 3 would also be supported on 400 series chipsets (meaning X470 and B450). I know that I shared this assumption, and I mentioned it in several blog posts. Now, with this new information, has AMD broken their promise?
Why Is This a Big Deal?
One of the advantages (and selling points) of the AMD Socket AM4 platform has been its longevity and backwards and forwards compatibility with different chipsets and processor generations. In most situations, it allowed you to use an older Socket AM4 processor in a newer generation Socket AM4 motherboard. It also let you use a newer generation Socket AM4 processor in a older generation Socket AM4 motherboard (with a BIOS update).
This made it possible to do easier piecemeal upgrades of an existing system for less money. For example, you could have bought a Ryzen 5 1600X along with an X370 motherboard when they were first released together in April 2017. Later, when the Ryzen 7 2700X was released in April 2018, you could flash the BIOS of your X370 motherboard, and then use your new Ryzen 7 2700X in your existing motherboard. This is called an “in-socket” upgrade.
By contrast, Intel has had a long historical pattern of forcing more frequent motherboard upgrades when new generation processors were released. This has caused a lot of resentment and angst in the hardware community over the years.
Now, with this new announcement from AMD, there is quite an uproar among some people in the hardware enthusiast community. There are accusations that AMD is acting like Intel, they have broken their compatibility promise, they are greedy, etc.
Since the B550 chipset has been delayed for so long, many people have bought inexpensive B450 chipset motherboards to use with lower-end AMD Socket AM4 processors, with the plan of being able to do an in-socket upgrade to a Zen 3 processor later. Now, it seems like that won’t be possible. This has generated some anger.
Is There a Good Explanation for This Change?
In some respects, yes there is. The official justification is that the flash ROM on some older motherboards is too small (in terms of storage capacity). There is not enough space to support a whole new generation of processors. The industry standard size for many years has been 16MB. Some existing B450 motherboards have a 32MB ROM BIOS, but this is rare. These are special order items, that increases the BOM cost for the motherboard. The profit margins on budget motherboards are pretty tight, so using a larger ROM BIOS can be an issue.
The more likely technical reason is that AMD (and the motherboard vendors) don’t have enough development and testing resources. This makes it difficult to test and support so many different processor and chipset combinations.
One way to simplify this development and support matrix (and free up space in the BIOS) would be to drop support for some older and less common CPUs in new BIOS versions. Unfortunately, there are valid fears that this approach would cause a lot of confusion and support issues.
For example, imagine you had an older Ryzen 7 1700X CPU in a B450 chipset motherboard. In order to free up space in the ROM BIOS to support new Zen 3 processors, the motherboard vendor decided to drop support for the older Zen processors in a new BIOS version. If you installed that new BIOS version, your system would be bricked, and you would probably be pretty upset.
A number of other people have opinions and commentary on this issue.
- How AMD Sabotages Itself & Both Sides of the Story (B450 / B550 Chipsets & Zen 3 BIOS)
- AMD plus Zen3 = AM4+ ? Chipset Roulette v2
- AMD Does An Intel, Axes Zen 3 on 400-Series Motherboards, Our Thoughts
Personally, I am a little disappointed by this new announcement, but I am not angry. My main concern is that I inadvertently gave some bad advice about buying B450 motherboards. There is nothing wrong with good B450 motherboards, but their upgrade path is cloudy now.
I think AMD will relent in some cases where the motherboard maker wants to have a beta BIOS that will let a specific B450 chipset motherboard support Zen 3 processors. I think this will probably happen with MSI for example. MSI has previously made more explicit promises about supporting ALL Socket AM4 processors in their B450 MAX motherboards. They might be in some legal trouble if they don’t do something like this.
The upcoming B550 chipset motherboards will probably cost between $80-150, depending on the model. Buying one of those to go with a future Zen 3 processor would be a nice upgrade for not too much money. I also think it is likely that there could be a new high-end “X670” or “X590” chipset that works with Socket AM4 motherboards. These motherboards would be released when the Zen 3 processors are released (or soon thereafter). If that happens, that would be my first choice if I was going to buy a high-end Zen 3 processor.
What did you think? Is this a big deal that makes you angry with AMD? Please let me know in the comments. Thanks for reading!