Remember that characteristically quirky Asrock motherboard (opens in new tab) that transmogrified from an AMD B650 board into an X670? Well, Asus has got something similar going on with its new ROG X670E-I board. It has a chipset on a PCIe stick.
How so? Well, this all hinges on the fact that AMD’s B650 chipset uses a single chip, known as Promontory 21, whereas the premium X670 chipset houses two Promontory 21 chips daisy-chained together.
It’s basically a more cost effective way of adding features and connectivity compared with taping out two different chips or going with a single larger chip and switching off various features for the lower-end implementation.