ASRock has developed a card that can expand a specific B650 motherboard via a specific connection as if it were an X670 motherboard. It appears to be primarily I/O expansion in the form of additional USB and M. 2 connections and faster network support.
LevelOneTechs has one custom video For the so called X670 Xpansion Kit. This website has tested this expansion card with ASRock’s B650 LiveMixer motherboard. The card adds a second chip to this motherboard. X670 motherboards have two Promontory 21 chips, while B650 motherboards have to do one. Additional options are available in the motherboard BIOS to manage the second chipset.
The expansion card has two M.2 slots with PCIe 4.0 x4, three USB-A connections, one USB-C connection up to 10Gb/s, two SATA connections, and one 10Gb Ethernet connection. The latter is perhaps the most striking addition, since the tested motherboard only exceeds 2.5G in terms of network speed support.
X670 Xpansion Kit must be connected in a certain way, ie via PCIe in combination with a special cable, control line Which requires a J2 header on the motherboard. As a result, the card will only work on certain motherboards.
It is not clear whether this X670 Xpansion Kit expansion card is a product that will be released in this form, and if so, when this product will be released. It appears to be a more developed version than just a prototype. The B650 LiveMixer motherboard used by LevelOneTechs has not been officially released yet.