Many laptop computers have SD card slots, and they aren’t just for transferring data from cameras or game consoles. You can keep an SD card in your laptop as permanent storage, just as you would with a phone or tablet, but is it a good idea?

Even the fastest SD cards are much slower than the solid state storage used in most laptops, and sometimes slower than even traditional hard drives. That being said, it still makes sense as an option for some file storage, especially for computers that don’t have any other upgrade or expansion options. As long as you know the strengths and weaknesses of SD storage, and you have the right card, it can be a useful upgrade.

Choosing Your Battles

It’s not a good idea to use SD cards for any and all data you might keep on your computer. The much slower transfer speeds are fine for some types of data, but some applications and games will slow down dramatically when using SD card storage, if they work at all. That’s why the faster SD Express standard was created, but the built-in card readers on most laptops can’t use SD Express.

Most budget and mid-range laptops use eMMC or SATA-based solid state storage with decent performance, with sequential read speeds somewhere around 300–600 MB/s. Higher-end computers usually have NVMe SSDs with significantly faster drive speeds. My MacBook Pro with an M4 Pro chipset clocks in at around 6,400 MB/s on the internal drive, as seen below in the AmorphousDiskMark benchmark.

For comparison, the absolute fastest full-size SD cards have sequential read and write speeds of around 300 MB/s, like SanDisk’s Extreme Pro cards. Most SD and microSD cards are slower than that—a 64GB SanDisk Extreme A2 microSD card in my MacBook’s SD card slot couldn’t even reach the advertised 92 MB/s sequential read speeds.

Here are some example use cases where SD card storage should have acceptable performance:

• Documents and other small files
• Photos, videos, and movies, but transferring movies will probably be slow
• Retro emulators (pre-PS2 consoles, DOSBox, MAME, etc.)
• Legacy PC games
• Local music library
• Offline Wikipedia or similar databases with Kiwix

Here are some use cases where you should not use SD card storage:

• Modern PC games
• Video editing
• Data backups

There are exceptions to most of these use cases, but hopefully this gives you a better picture of what you can expect with SD storage in a laptop. It’s not a completely pointless option for expanding your available storage, but there are more drawbacks than you might expect.

Pick a Fast Card

Not all SD cards are equal, and when read and write speeds are already so limited, using one of the fastest cards is crucial. The main specification you should be looking for is the Application Performance Class, indicated by an “A1” or “A2” label on the card. That tells you the card has better performance for random read and write operations, which is important when jumping between files or running software straight from the card.

If your laptop has a microSD card slot, cards like the Samsung EVO Select A2 or SanDisk Extreme Pro A2 are great options. If your laptop has a full-size SD card slot, check out SanDisk’s Extreme Pro card or a Samsung Pro Ultimate card.

If you already have a spare SD card with A1 or A2 speeds, you’re good, just don’t expect great results with older cards or no-name brands. You can test a card’s performance with benchmarks like CrystalDiskMark on Windows and AmorphousDiskMark on Mac.

Check The Size

Most laptops with microSD card slots, like some Chromebooks, can store a connected SD card completely within the laptop’s frame. If you have a full-size SD card slot, the card might stick out of the side of the laptop, potentially damaging the card or the computer if it snags on something.

For computers with a regular SD card slot, the best option might be to use a flush BaseQi adapter or other similar device, paired with a fast microSD card. That way, the card and SD slot won’t stick out (as far) from the laptop.

Check Out The Alternatives

An SD card might not be your only option for adding more storage to your laptop. You might have a standard SATA, M.2, or NVMe slot that can be upgraded to use a larger drive, and some laptops (especially gaming and workstation PCs) have more than one drive slot. Try doing a web search for your laptop model’s repair or servicing manuals for more information.

Replacing internal drives is certainly more annoying, especially with migrating the operating system and other existing data, but PC internal storage will always be significantly faster than SD cards. If you don’t want to try it yourself, many PC repair shops (including chains like Best Buy) can do it for you.

There are also low-profile flash drives that can serve the same purpose, like the Samsung’s FIT Plus. Those drives can offer better performance than SD cards, but they take up a USB port, and they stick out of the computer.

Modern laptops don’t have many options for adding storage, leaving the SD card slot as one of the best options. Still, you should be aware of the limitations, and take another look at alternatives like internal drive upgrades and USB drives.