PC builders looking for more storage and connectivity without replacing an entire motherboard are starting to notice a new trend coming out of China: custom add-in cards (AICs) that use actual AMD 800- and 600-series chipsets, including X870, X670, and B650. These expansion cards plug into a standard PCIe slot and can dramatically increase I/O options on systems that are limited by entry-level or older motherboard layouts.
One of the most talked-about examples comes from an open-source hardware platform known as Oshwhub. According to content shared by a creator on Bilibili, these boards are designed around an AMD Promontory 21-series “southbridge” (the same family used in modern AMD chipsets) and can function like a typical PCIe device across different PC platforms. In other words, the card essentially brings its own chipset-based expansion capabilities, rather than relying solely on controllers integrated into the motherboard.
Interestingly, many of these chipset-based AICs were originally produced by AMD for testing and evaluation. Over time, a noticeable number have made their way into the DIY market through third-party sellers, creating an unusual but appealing upgrade path for enthusiasts.
While several variants exist, many of the commonly sold models are based on the B650 chipset, with higher-end options featuring X670 or X870. The main differences between these versions come down to how many PCIe lanes and USB features they can offer. As expected, the more premium chipsets generally deliver broader expansion potential than entry-level designs.
A standout option being sold is commonly referred to as the “B650 PCH PCIe 4.0 Expansion Card.” It includes a B650 chipset under a small heatsink and connects via a PCIe 4.0 x4 interface. Despite that modest link, it delivers a surprising amount of expansion hardware, including four M.2 slots capable of PCIe 4.0/3.0 x4 operation, four SATA III ports, and USB 3.2 support. Pricing reported in China is around 300 RMB, roughly $40 USD, making it an eye-catching value for users who need more SSD and SATA connectivity.
There are also older X570-based expansion cards showing up for even less, with pricing cited around 200 RMB (about $30 USD). These tend to provide similar M.2 and SATA functionality, while also adding more USB ports, including Type-A and Type-C options. In addition, some motherboard makers have offered their own chipset-based add-in expansion kits bundled with certain products, sometimes including extras like 10 GbE LAN support depending on the implementation.
One of the more unusual capabilities is that some of these AIC expansion boards can be “daisy-chained.” Certain models include an onboard PCIe 4.0 x4 slot that can, at least in theory, be used to connect another expansion board and continue stacking I/O. It’s not exactly practical for most builds due to space, cooling, and bandwidth considerations, but it highlights how far this concept can be pushed.
When it comes to real-world results, reported performance is said to be comparable to onboard controllers for the features provided, including full-speed M.2 Gen4x4 operation, USB 3.2, and SATA III. That makes these cards more than just a novelty—they can be a legitimate way to modernize an older system or add serious expansion to a budget build.
There is one important catch: users may need to update the firmware before these cards work properly. Sellers reportedly provide the necessary firmware and support through social channels, which is helpful, but it also means buyers should be comfortable with a bit of DIY setup before expecting plug-and-play behavior.
For anyone trying to add more M.2 SSD slots, expand SATA storage, or boost USB connectivity without upgrading their entire platform, these AMD X870, X670, and B650 chipset-based expansion AICs are shaping up to be a clever, low-cost workaround—especially for entry-level Intel and AMD PCs that don’t have robust I/O to begin with.
