Most people plug the usual stuff into their motherboards—CPUs, GPUs, RAM, SSD, etc. That doesn’t mean these are the only devices your motherboard could handle. Far from it!
PC hardware is a collection of open standards after all, so as long as a piece of hardware complies with, for example, PCI Express, you can make pretty much anything, just like these uncommon gadgets.
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POST Debug Cards: Reading the Motherboard’s Last Words
While many higher-end or enthusiast motherboards come with a POST (Power-on Self-Test) card built in, that’s not the case for most. If you’re trying to figure out why a computer won’t turn on, you can often use a POST debug card that will give you an error code on its display telling you exactly what’s going wrong and at what phase of the boot process things have gone wrong.
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TPM (Trusted Platform Module) Chips: Suddenly Famous
Until the advent of Windows 11, most people had never even heard of a “TPM” or Trusted Platform Module. It was something you got in business computers meant for large corporations, not the average person’s laptop or desktop. Unfortunately, a TPM 2.0 is a hard requirement for Windows 11, which means that if your computer doesn’t have one you’re out of luck and will have to either get rid of that PC or move over to Linux.
Some motherboards can accept a proprietary TPM module, which can help make those computers compatible with Windows 11, assuming this was the only requirement that the computer didn’t meet.
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Wi-Fi and Bluetooth Expansion Modules: Wireless by Design
Desktop motherboards often leave out wireless networking to keep costs down, but many are designed with future expansion in mind. Some boards use M.2 Key-E slots or proprietary headers where you can add a Wi-Fi and Bluetooth module.
This is especially common with mid-range or business-class boards, where manufacturers might sell different SKUs of the same model—one with Wi-Fi, one without. If you bought the cheaper one, adding the module yourself is the “official” upgrade path. It saves you using up one or more USB ports, or PCIe slots on the board.
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Fan and RGB Controller Boards: Because One Header Isn’t Enough
Gamers and case modders can chew through fan headers fast. Between CPU coolers, case fans, and RGB strips, even a feature-packed motherboard can run out of connections. That’s where fan and RGB controller boards come in. Once you’ve plugged the header into the motherboard, it acts as a hub for all the lighting in the system, letting you control many more fans and lights.
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M.2-to-Everything Adapters: The Swiss Army Knife Slot
M.2 slots are best known as the home for NVMe SSDs, but they’re really just a physical connector for PCIe or SATA lanes. That means with the right adapter, an M.2 slot can host all sorts of hardware: SATA expanders, network cards, or even cellular 4G/5G modems with SIM slots. I’ve even seen people use an M.2 slot to give laptops access to a full GPU at faster speeds than normal eGPU interfaces like Thunderbolt or OcuLink.
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Capture and Tuner Cards: Old-School Meets Streaming
While most people these days probably prefer using a USB-based capture device to digitize video, you can still get capture cards that go in a PCIe slot, and there are legitimate reasons to prefer this over USB.
The biggest reason is bandwidth, because if you make full use of the PCIe interface you can capture multiple streams with ease, or capture a single stream at crazy-high quality levels.
Some old tuner cards are useful for capturing analog signals, and in some cases a modern USB tuner cards may not have all the connections you need to archive vintage media. Besides, modern digital TV tuner cards are also a thing.
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Dedicated Sound Cards: Still Kicking in the Audiophile Era
I still remember what a big deal it was when we got our first sound card. Up to that point I had to be happy with the beeps and boops of a PC speaker, but a sound card (while expensive) opened up an entire world of multimedia.
However, it wouldn’t be long until audio capabilities were built directly into motherboards, and for most people a dedicated sound card became completely unnecessary for their needs.
That doesn’t mean the dedicated sound card is dead. That couldn’t be further from the truth. No, these days dedicated soundcards tend to be aimed at professionals and audiophiles who want better fidelity, and pure noise-free sound. A gaming sound card like the Creative Sound Blaster Z SE promises support for surround sound, low latency, and extremely high-quality sound reproduction.
3
RAID and HBA Cards: The Homelabber’s Playground
RAID controllers and Host Bus Adapters (HBAs) are PCIe cards designed to connect lots of drives. If you’re building a NAS or home server, these let you expand beyond the four to six SATA ports that a consumer motherboard usually offers.
These cards are staples in datacenters and have been embraced by Homelab enthusiasts who want enterprise storage tricks on consumer hardware. With the rise of self-hosted servers at home, these cards may not be so “uncommon” in future.
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Thunderbolt Add-In Cards: When You Need Speed
Many laptops ship with Thunderbolt these days, but it’s less common on desktop systems. If you have a motherboard that supports it, you can add Thunderbolt ports to your system, but it’s important to emphasize this will only work on specific motherboards with the right proprietary header.
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Industrial and Specialty Cards: The Real Oddballs
Finally, we come to the strangest cards of all. Some motherboards can host expansion cards for highly specific industries: serial and parallel port adapters for legacy hardware, CAN bus interfaces for automotive diagnostics, or FPGA development boards for hardware engineers.
These cards rarely make sense in a gaming rig, but they show just how flexible the PC platform is. Whether you’re controlling machinery, experimenting with hardware design, or just trying to get an old printer working again, there’s probably a card for that!