Out of M.2 slots? This $20 adapter unlocks hidden storage on your motherboard
Depending on your computer and motherboard, you may or may not have many storage options. The best motherboards come with a ton of M.2 slots, but in others, you might be lucky to have two – and sometimes you’ll only get one.
Fortunately, if you want to continue adding storage to your computer, you still have options if you’re willing to get creative.
Full PCIe slots
The most realistic option
When you’ve exhausted your motherboard’s dedicated M.2 slots, using your available full-size PCIe slots is usually the most efficient and high-performance solution. Motherboards typically feature multiple PCIe slots of varying lengths and bandwidths, such as x4, x8, or x16 slots, which are traditionally used for graphics cards, sound cards, or high-speed network cards. You may not have a graphics card, or you may have one, but you could still find yourself with unused PCIe slots that you don’t know what to do with. In these cases, it is a good choice for you.
By purchasing a PCIe to M.2 NVMe adapter card, you can easily install a new NVMe SSD directly into one of these available lanes. These adapters are relatively inexpensive and function as a passive bridge, routing data from the M.2 drive directly to the motherboard’s PCIe bus. Since NVMe drives use the PCIe interface to communicate with the CPU anyway, installing a drive via an adapter into a standard PCIe slot allows it to operate at its maximum intended speed, provided the slot provides adequate bandwidth.
A standard modern NVMe drive requires four lanes of PCIe bandwidth, often referred to as PCIe x4. Therefore, placing an adapter in a x4 or higher slot will ensure optimal read and write speeds without creating a bottleneck. And since PCIe slots normally have more lanes than that, you can even create multiple drives. For users wanting to add multiple drives at once, there are also multi-slot PCIe adapter cards available on the market.
However, using these multi-drive cards requires a specific motherboard feature called PCIe bifurcation. Bifurcation allows a single high-bandwidth slot, such as an x16 slot typically reserved for a graphics card, to be divided into smaller segments, such as four x4 segments, allowing the system to recognize and address multiple individual drives on a single expansion card. Before purchasing a multi-drive adapter, it is crucial to check your motherboard’s base I/O system to ensure that PCIe bifurcation is supported; otherwise, the system will only recognize the first drive.
Electronic key slot
An alternative hack
A lesser-known method for adding an M.2 drive is to reuse the M.2 E-Key slot on your motherboard. This is commonly seen on laptops and desktop motherboards with built-in Wi-Fi. Unlike standard M.2 M-Key slots designed specifically for high-speed NVMe storage, the E-Key slot is primarily designed for wireless network cards, providing Wi-Fi and Bluetooth connectivity to the system. If your computer uses a wired Ethernet connection or a dedicated USB Wi-Fi adapter, this built-in slot may remain empty and can technically be converted for storage purposes.
Converting an E-Key slot requires a specialized adapter ribbon or small circuit board converter that transforms the physical E-Key interface into an M-Key slot capable of accepting a standard NVMe SSD. It’s a little hacky, but it’ll do the trick.
While this is a smart way to squeeze an extra drive into a cramped system, there are important performance tradeoffs to understand before proceeding. The physical and electrical architecture of the E-Key slot is fundamentally different from a dedicated storage slot. Typically, an E-Key slot is wired for only one or two PCIe bandwidth lanes, represented by PCIe x1 or x2. Since standard NVMe drives are designed to saturate four lanes, significant data throttling will occur.
Installing a high-performance drive through an E-Key adapter will hamper its maximum sequential read and write speeds, cutting its theoretical performance in half or worse, depending on the motherboard’s specific lane configuration. Beyond electrical limitations, physical space often poses a significant obstacle. E-Key slots are frequently positioned in tight areas of the motherboard, often near the rear I/O panel, leaving insufficient space for a standard 80-millimeter-long M.2 drive. As a result, users often have to use flexible flat cable adapters to route the storage slot to an open space inside the chassis, complicating internal cable management. You can also use smaller M.2-2230 drives, but these are more expensive, especially in larger sizes.
Other options
There’s more to life than M.2
The simplest alternative is to move away from the M.2 form factor altogether and use your motherboard’s traditional Serial ATA, or SATA, ports. It’s sad, but it’s probably the most realistic option. Modern motherboards typically include four to eight SATA ports. By purchasing a standard 2.5-inch SATA SSD, you can get a substantial increase in storage volume at a cost per gigabyte that is typically lower than high-end NVMe drives. Although SATA drives have a hardware interface speed limit of around 600 MB per second, which is significantly slower than modern NVMe technology, this speed is still more than sufficient for mass media storage, document archiving, and playing the vast majority of video games.
Alternatively, if portability or ease of physical installation is a priority, external NVMe enclosures offer a high-speed plug-and-play solution. These external enclosures allow you to place a standard M.2 drive inside a protective metal shell that connects to your computer via a USB-C cable. The performance of an external enclosure depends entirely on the specific USB protocol supported by both the enclosure and your computer’s external ports. Using a standard USB 3.2 Gen 2 port will produce speeds of around 1,000 megabytes per second, while more advanced USB4 or Thunderbolt 4 enclosures can rival internal speeds, pushing up to 4,000 megabytes per second.
One option makes more sense than others
The most realistic option for most people is to simply use whatever PCIe slots you have left. But if you can’t do that, any of these options should do the trick. It’s not impossible, you just need to be more creative.
