Puny Asus Mini-ITX motherboard has a chipset on a stick

Asus ROG X670E-I
(Image credit: Asus)

Remember that characteristically quirky Asrock motherboard 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.

Anywho, whereas the Asrock board was all about quirky for the sake of quirky, the Asus item is a function of more practical concerns. The Asus ROG X670E-I is one of those puny Mini-ITX models which poses a challenge for laying out a dual-chip chipset.

So, as Tom's Hardware explains, Asus has whacked the second Promontory 21 chip on a PCIe 4.0 x4 add-on card. The net result is an extra two USB 4 Type-C ports with a 40 Gbps throughput as well as DisplayPort support, a Wi-Fi 6E + Bluetooth 5.2 adapter, a 2.5GbE controller, and multiple further USB ports.  

The Asus ROG Strix X670E-I board also sports two M.2 slots, one in PCIe 5 spec the other PCIe 4, a couple of SATA ports (via another included add-on card), two further USB4 Type-C connectors, one USB 3.2 Gen2 Type-C port, six USB 3.2 Gen 1 Type-C connectors, and five USB 2.0 ports.

Asus ROG X670E-I

Figure 8 on Asus's schematic shows the second chipset chip situated on a quad-lane M.2 card. (Image credit: Asus)

Plus you get 2.5GbE and high quality audio courtesy of the Realtek ALC4050 codec and ESS Sabre 9260Q DAC.

Broadly speaking, these add-in chipset cards require specific UEFI support. So, you can't just whack them into any AMD AM5 motherboard that already has a Promontory 21 chip and expect anything good to happen.

But as these modular motherboards emerge it at least seems like AMD's dual-chip approach is giving motherboard makers plenty of options.


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Jeremy Laird
Hardware writer

Jeremy has been writing about technology and PCs since the 90nm Netburst era (Google it!) and enjoys nothing more than a serious dissertation on the finer points of monitor input lag and overshoot followed by a forensic examination of advanced lithography. Or maybe he just likes machines that go “ping!” He also has a thing for tennis and cars.