A Redditor has showcased an unusual PCIe adapter/extension card that adds two extra M.2 slots while keeping enough PCIe bandwidth for modern mid-range GPUs. Perfectly dimensioned to be paired with low-profile graphics cards, this adapter works like a riser card, taking advantage of the leftover space to provide two M.2 SSD slots. Let me explain.
The adapter takes advantage of the PCIe bifurcation feature available on some modern platforms, which consists of splitting one physical PCIe x16 slot into multiple independent logical links. Instead of a single device using all 16 lanes, PCIe bifurcation allows to electrically divide the available lanes into x8/x4/x4 or x4/x4/x4/x4 without needing a PCIe switch chip.
Thanks to this, an adapter can allocate eight lanes to the graphics card and eight lanes to SSDs (two x4 connections). In other words, it allows you to install a graphics card plus two NVMe SSDs on the same PCIe slot, all working at the same time. That said, it’s important to keep in mind that PCIe bifurcation isn’t universally available, though modern mid- and high-end hardware tends to support it.
The adapter in question is conveniently designed to be paired with low-profile graphics cards, especially those that only take advantage of x8 PCIe lanes, like the Nvidia GeForce RTX 4060. As I’ve explained, it takes advantage of the leftover room and PCIe lanes to add two M.2 slots (one on each side of the PCB) while acting as a passthrough/riser for the remaining x8 lanes. This means that in most PC cases, you would be able to install one low-profile graphics card plus two M.2 SSDs in the same footprint as a regular graphics card.
Some may remember that Asus RTX 4060 Ti card, which had an M.2 slot on its back. Well, this is pretty much the same idea, just with two M.2 slots, and a design compatible with any other GPU or add-on card. For instance, a consumer review on Amazon shows this adapter being used alongside another dual M.2 adapter, bringing the total to four x4 M.2 slots. A clever use case that can be handy on a compact Mini-ITX build or a high-speed NAS system.
The Redditor who shared this find has indicated using the additional M.2 slots to connect another GPU using an M.2 to PCIe adapter. With some help from the lossless scaling app, they could run game rendering on the main RTX 4060, while relegating frame generation or other tasks to the RTX 3060. Personally, I think the best use of such an adapter is to add more storage to a compact homemade NAS since a GPU isn’t required.
Interestingly enough, since this adapter doesn’t carry any advanced PCIe lane-splitting chip, its price is rather affordable, at just $26.99 on Amazon US. A nice option for those who like to push their hardware beyond design limitations.
