It will feature Dual-Chipset designs.
Taken from TPU … AMD is preparing to launch its highly-anticipated AM5 socket for the next generation of motherboards. And today, thanks to the sources over at Tom’s Hardware, we have information regarding memory support for B650 and X670 motherboards. According to the report, both B650 and X670 chipsets will limit the user’s memory option to the latest DDR5 memory standard, making it impossible for users with already existing DDR4 memory to perform a seamless upgrade to a new platform. So far, we don’t have a lot of details about Zen4’s integrated memory controller, and we can’t be certain if it supports DDR5 only or carries legacy DDR4 support. However, it seems like B650 and X670 motherboards will have no plans to enable the DDR4 standard memory usage.
Additionally, the report confirms that the B650 chipset is connected to the AM5 socket via PCIe 4.0 x4 connection and has eight lanes of PCIe 4.0 (four of which are for M.2 SSD), four SATA, and lots of USB ports. Documents suggest that the chipset-socket connection is available using PCIe 5.0 for some AM5 processors, so we have to wait and see how it works. As far as high-end X670 is concerned, this chipset is a combination of two chipset dies, presumably a combination of two B650 modules. This doesn’t work as the older north/southbridge type of a solution but rather doubled connectivity of a single B650 chipset. We have to wait for the official launch to confirm this information.
Source: TPU, Tom’s Hardware