But B5xx I also meant X570. Anyway, I am almost 100% sure, it won't work on A320, as the someone in the message abovedesired to run it on. And it is unclear if there will be updates for the BIOS for cheaper B450s.
Some A320 boards actually do support Ryzen 3000 with a BIOS update, like the one below. I wouldn't really recommend getting them because you'll probably need to flash the BIOS, but they can be used.
MSI seems to have committed to different support than AMD has. Gamers Nexus has covered the AMD chipset stuff recently to great detail.[0]
There are several issues that come together to make it difficult to support all AM4 CPUs across all the AM4 motherboards. MSI seems to have committed to their AM4 motherboards supporting all AM4 CPUs, and they are having to perform some gyrations (and potentially some reverse-engineering of AMD-supplied binary blobs) to meet their claims.
Please change the attitude. A320 does not officially support the 3100 and 3300x the poster above mentioned. Please pay attention when replying, otherwise you come across as rude.
Replying with supposition, "I am almost 100% sure, it won't work on A320," to vendor-supplied guidance (linked image in parent to supposition) on exactly what is and isn't intended to be supported comes across as rude. It makes it seem like there is no desire to engage in a conversation, but rather just to speak one's thoughts without regard to the partner. If the first response to engage with a specific user is to critique them for the gall of calling out that they're repeating themselves, it seems rather a callous disregard for others.
A320 supports Ryzen 1000-series, 2000-series, 2000-series APUs, and 3000-series APUs.
A320 does not support Ryzen 3000-series, and future Ryzen processors.
I can keep reading the linked chart for you, if you'd like.