Open source Switch 2 adapter brings M.2 NVMe SSD to Nintendo's latest console — MicroSD Express and NVMe share a similar pinout that could even theoretically support an eGPU

A gaming peripheral developer and console modder has shared details of their SDEX2M2 Adapter project. Despite the cryptic name, the project goal is a rather simple one – to create a reliable adapter for using the Nintendo Switch 2’s MicroSD Express card port to attach an M.2 NVMe SSD. The SDEX2M2 project is open source, and though it is still a work-in-progress, interested parties can visit the NVNTLabs GitHub page and check out extensive details of the components and schematics used.

Nintendo typically likes to lock down its consoles rather strictly, so seeing this kind of project at an advanced stage, so early after the launch of its Switch 2, might cheer console hackers and modders.

This storage mod “is possible because the Nintendo Switch 2's MicroSD Express slot supports the SD Express 7.1 standard, which exposes a true PCIe Gen3 x1 interface and utilizes the NVMe protocol for communication,” explains developer NVNTLabs on the SDEX2M2 GitHub project page. And, because the hardware adapter simply maps the appropriate pins from the Switch MicroSD Express slot to a standard M.2 2230 NVMe SSD, “no protocol translation is required as the Switch 2 host controller handles everything.”

Potentially big savings on storage expansion

For performance, users should expect data transfers up to approximately the limits of the PCIe Gen3 x1 interface, which is roughly 1 GB/s. That’s on a par with freshly launched cards from the likes of PNY. However, instead of spending $56 on a PNY microSD Express UHS-I U3 V30 A1 microSDXC Flash Memory Card with a measly 256GB capacity, you can get double the capacity with a Sabrent for the same price. We also see 1TB M.2 2230 NVMe SSDs, like the Patriot Viper Gaming VP4000 Mini 1TB M.2 2230 PCIe Gen4 x4 SSD for just $66. You will need to make/buy this new SDEX2M2 device first, though.

As a work-in-progress, there are still a few aspects of the SDEX2M2 design to iron out. Probably the biggest factor to be wary of is damaging your Switch 2 due to the use of an M.2 SSD that is too power hungry. NVNTLabs warns that any fellow modders who want to pick up and roll ahead with the design as it stands should “only use low-voltage, low-power M.2 2230 NVMe drives.” Also, despite physical similarities, users are asked not to insert this adapter into legacy MicroSD card slot-equipped devices like the original Nintendo Switch.

Adding an eGPU?

For now, this project shines the light on a possible way to attach cheaper storage for your Switch 2. However, PCIe isn’t just for storage, in modern PCs this high-speed interface is used for lots of other things like network and expansion cards, sound and capture cards, AI accelerators, and – of course – graphics cards.

The Nintendo Switch 2’s official specs confirmed the presence of an Nvidia Ampere architecture GPU similar to a mobile GeForce RTX 2050. Would it be possible to use the exposed PCIe Gen3 x1 interface to plug in some kind of eGPU?

There are indeed plenty of M.2 SSD slot to OCuLink adapters, but the available PCIe Gen3 x1 with 1 GB/s (8 Gbps) seems rather restrictive. Typically, we see eGPUs attach to devices using USB4 at up to 40 Gbps, or OCuLink at up to 64 Gbps, which can impact GPU performance, and also provide some context to how weedy PCIe Gen3 x1 is.

Moreover, there would probably have to be some more modding required for the Switch 2 to use the eGPU rather than the onboard GPU for video out. We can’t say it is impossible, but it would be an impressive feat to get such a setup working.

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