You can install Nvidia's fastest AI GPU into a PCIe slot with an SXM-to-PCIe adapter -- Nvidia H100 SXM can fit into regular x16 PCIe slots

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By Matthew Connatser
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For the low low price of $16.

An adapter board for H100 SXM GPUs to PCIe.
(Image credit: @I_Leak_VN on X)

An adapter that allows H100 SXM GPUs to use a PCIe connection is available through retail outlet Xianyu for just $16 (via @I_Leak_VN on X). SXM, or server PCIe module, is a form of PCIe that Nvidia has used since 2016. Though Nvidia has always offered SXM and PCIe versions of its datacenter GPUs, this adapter will permit owners of SXM cards to use them in regular x16 PCIe slots.

The listing for this adapter is on Xianyu, the secondhand or used version of Taobao, a Chinese retailer. The seller hasn't included many details in the listing; they say the adapter is for SXM 5 (which is what Hopper GPUs like H100 use) and that they "don't know if it's good or bad yet," which may speak to the quality of the product. When the listing was screenshotted and shared on X, the price was 114 Yuan or about $16, a 400 Yuan discount from its original price of 514 Yuan or $70.

Because the adapter requires compatibility with SXM 5, it's unclear whether Nvidia's latest Blackwell B100 or B200 GPUs are compatible. Nvidia hasn't disclosed if Blackwell SXM GPUs will introduce a new version of SXM, but precedent implies we will see SXM 6 with Blackwell. So far, every new generation of Nvidia GPUs has introduced a new version of SXM, and it almost always only works with that one version, so it's unlikely we'll see Blackwell in this specific adapter.

The utility of this kind of adapter is questionable. Nvidia already sells a PCIe version of the H100, and putting a perfectly good H100 with SXM ports on this converter board seems somewhat pointless. Given that the H100 is the GPU of choice for cutting-edge datacenters and AI supercomputers, relying on a sketchy adapter doesn't seem like a smart idea.

However, there might be a decent reason why this adapter exists: supply. Although supply for the H100 has improved from a lead time of up to 11 months to three months, it's not ideal and implies a significant shortage still exists. Buyers of the H100 might not have the luxury of choosing either the SXM or PCIe model, so perhaps this adapter exists because there was a lot of demand to convert SXM cards into PCIe.

It's hard to say how many of these adapters have been produced or if they're seeing actual use in systems. Unfortunately, this single Xianyu listing doesn't tell much, especially since it's for selling used products. 

Matthew Connatser
Matthew Connatser

Matthew Connatser is a freelancing writer for Tom's Hardware US. He writes articles about CPUs, GPUs, SSDs, and computers in general.

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5 Comments Comment from the forums
  • NinjaChemist
    I can finally run Crysis!
    Reply
  • artk2219
    That adapter probably exists so you could theoretically use a standard desktop with it and save on platform costs, or you want to plug them into an older server that likely doesn't have any sxm ports. I can see the value in an adapter like that, especially if you just want to test something before committing to a full platform purchase.
    Reply
  • digitalgriffin
    These are commonly used to prototype test boards on a common off the shelf platform. It is easier to debug/analyze in a common system then hooking up to a server rack.
    Reply
  • bit_user
    artk2219 said:
    That adapter probably exists so you could theoretically use a standard desktop with it and save on platform costs, or you want to plug them into an older server that likely doesn't have any sxm ports.
    Yes. Older or not, SXM sockets aren't a typical server feature.

    artk2219 said:
    I can see the value in an adapter like that, especially if you just want to test something before committing to a full platform purchase.
    No. This is a pretty terrible way to evaluate these GPUs, because SXM is about scaling and connecting up multiple GPUs into a mesh network.

    Not only that, but there's no way in heck anyone would ever recommend this as a way to evaluate SXM-based GPUs, since they have passive cooling and rather steep airflow requirements.

    IMO, what this is about is enabling people to buy old, used SXM GPUs off ebay and plug them into a home workstation/server to use for some extra compute power. That probably also helps explain why it's so inexpensive.
    Reply
  • bit_user
    NinjaChemist said:
    I can finally run Crysis!
    Only using a V100 or older. Newer 100-series GPUs have little or no raster acceleration. Also, SXM doesn't have display outputs, so you'll have to pair it with a regular GPU to do the display output.
    Reply