AMD will now support the Zen 3 and Ryzen 4000 CPUs on the bit older B450 and X470 motherboards. This is an end result of community backlash. Earlier, AMD said it will not provide the support, contradicting its earlier claims. Nobody liked that. As expected, this will require a BIOS using the supported AGESA code.
However, there are limitations. Due to the ROM capacity limitation, AMD will have to remove some features to support Zen 3 and AMD 4000 CPUs. Using the new AGESA equipped BIOS disables support for many current-gen Ryzen CPUs. It will also disable BIOS rollback. Once you go updating the BIOS with the supported AGESA code, you can’t go back.
The caveats mentioned by AMD are as follows:
- We will develop and enable our motherboard partners with the code to support “Zen 3”-based processors in select beta BIOSes for AMD B450 and X470 motherboards.
- These optional BIOS updates will disable support for many existing AMD Ryzen™ Desktop Processor models to make the necessary ROM space available.
- The select beta BIOSes will enable a one-way upgrade path for AMD Ryzen Processors with “Zen 3,” coming later this year. Flashing back to an older BIOS version will not be supported.
- To reduce the potential for confusion, our intent is to offer BIOS download only to verified customers of 400 Series motherboards who have purchased a new desktop processor with “Zen 3” inside. This will help us ensure that customers have a bootable processor on-hand after the BIOS flash, minimizing the risk a user could get caught in a no-boot situation.
- Timing and availability of the BIOS updates will vary and may not immediately coincide with the availability of the first “Zen 3”-based processors.
- This is the final pathway AMD can enable for 400 Series motherboards to add new CPU support. CPU releases beyond “Zen 3” will require a newer motherboard.
Setting realistic expectations
Battling the ROM capacity is not very easy and therefore was the only way to provide support. We might see these BIOS with bare GUI designs. I am sure many will appreciate a straight-forward less glowy UEFI interface. It would also be interesting to see if certain feature sets can be provided with this optional BIOS. There’s a very good chance that motherboard manufacturers might provide support for some of its B450 and X470 motherboards. But hey, its something. That’s what users needed as AMD did make that subtle assurance.
Naturally, the ability to use Zen 3 and Ryzen 4000 series CPU will not enable PCIe 4.0 bandwidth. AMD B550 and X570 chipsets are the only ones support PCIe 4.0 lanes.