MicroSD cards may not be as prevalent as they used to be among the best smartphones, but they continue to serve as a reliable storage solution for things like digital cameras, drones, and handheld consoles like the Steam Deck and its alternatives. They even serve as drives for the operating system and software on single-board computers like the Raspberry Pi, so it's safe to say that they're still very relevant.

Not all microSD cards are created equal, though, and there are plenty of features and specifications to consider while making a purchase decision. There's also a confusing array of memory card logos, specifications, and just types to consider, so there's more to buying a microSD than simply picking the one with maximum capacity for the price. If you are in the market to buy a new SD card and are overwhelmed by all the options, here are a few important things to remember.

Types of SD cards: Difference between SD, miniSD and microSD

The first thing you need to consider is whether you need an SD or a microSD card. You might've guessed this from the name, but the microSD card is essentially a smaller version of an SD card. Here's a quick look at the physical dimensions of each type:

• Standard SD cards: 1.26x0.94x 0.083 to 0.055 inches (32x24x2.1-1.4mm)
• miniSD cards: 0.85x0.79x0.055 inches (21.5x20x1.4mm)
• microSD cards: 0.56x0.43x0.039 inches (15x11x1mm)

There's another type called miniSD that used to slot between the standard and the microSD cards in terms of physical dimensions. MiniSD cards, however, are no longer produced due to the market domination of microSD cards, and it's safe to say that you'll only come across standard SD and microSD cards on the market these days.

The best thing about microSD cards is that they slot right into a standard SD card slot with an adapter that's commonly available. In fact, many microSD cards come bundled with a standard SD card adapter, so you can use the same card with gadgets that only have an SD card. That said, you can't insert a standard SD card in a microSD card slot due to the obvious size limitation.

Besides the physical size difference, though, both SD and microSD cards share the same capacity and speed classes. This means you're not missing out on any additional capacity or performance benefits by opting for one over the other, so it's better to pick the type of card that's accepted by the device you want to use it with. Yes, you can insert a microSD card in a standard SD card slot with an adapter, but I only recommend it if you want to quickly access the files in a pinch and not in devices like a digital camera that needs constant access to the SD card.

Once you've narrowed out the type of SD card to buy, it essentially comes down to the capacity and speed classes. They're both crucial metrics to consider while shopping for an SD or a microSD card, as not all of them are geared towards demanding tasks, such as recording high-definition video.

Storage capacity classes

Both SD and microSD cards can be categorized into five different size classes, which indicate the connection system and the overall capacity of the card.

• Best microSDSC card

  Transcend TS2GUSDC 2GB microSD card

  $9 at Amazon
• Best SDHC card

  SanDisk 32GB Extreme PRO SDHC UHS-I card

  $14 at Amazon
• Best microSDHC card

  PNY 32GB Elite microSDHC card

  $9 at Amazon
• Best SDXC card

  Lexar Professional 1066x SDXC card

  $30 at Amazon
• Best microSDXC card

  Samsung EVO Select microSD

  $10 at Amazon

SDSC, SDHC, and SDXC cards are readily available on the market these days, and they work with various devices, including laptops, smartphones, digital cameras, handheld consoles, and more. SDXC cards are pretty common these days since the need for more storage is constantly increasing for data like bigger game files, high resolution photos and video footage. SDUC cards are still relatively new, with no commercial products that are readily available to purchase.

Speed classes

SD cards have evolved a lot over the years, with each new revision bringing better performing cards with faster transfer speeds. The performance improvement you get with each revision is essentially a direct result of either more contact points to provide more channels for the data or higher bus clocks. The SD cards are categorized into different speed classes based on the peak bus throughput, which essentially indicates the maximum amount of bytes/sec that can be transferred between the card and the host.

You don't necessarily need the fastest SD card out there if you are a casual user planning to use it for storing files on your smartphone. The speeds matter more if you are, say, a professional photographer taking a bunch of photos in quick succession and saving them in a high-resolution RAW format. Modern handheld gaming consoles also demand a fairly fast SD card to load the game files in real time.

There are four different Speed classes, two Ultra High Speed, and as many as five Video Speed classes for SD and microSD cards based on guidelines provided by the SD Association. They are as follows:

The regular SD cards with a Speed class rating are readily available on the market, and they're worth considering if you want lots of storage for cheap. Class 2 is the slowest of them all, with 2MB/s, whereas Class 10 is the fastest. The Class 10 cards are perfect for most users as they strike the right balance to offer the best-performing cards at a reasonable price.

• Class 10 microSDXC card

  SanDisk 256GB Ultra microSDXC card

  $33 at Amazon
• Class 10 SDXC card

  SanDisk 256GB Ultra SDXC card

  $33 at Amazon

The Ultra High Speed (UHS) 1 and 3 are also fairly popular among enthusiasts with devices designed for professional use. Cards with a U1 rating have identical speeds to that of Class 10 (C10). U3 cards, on the other hand, offer slightly better speeds, making them ideal for demanding workloads.

• Best microSDXC U3 card

  TEAMGROUP GO microSDXC card

  $18 at Amazon
• Best microSDXC U1 card

  Samsung PRO Endurance MicroSDXC Memory Card

  $40 at Amazon

Lastly, Video Speed cards can be classified into five different types, each of which is suitable for different video recording devices. Both V6 and V10 cards are ideal for standard videos, while the V30 and V60 are ideal for HD/FHD and 4K recording, respectively. You can also grab V90 cards in case you're planning to use high-end recording devices for up to 8K video recording.

• Best V10 microSDHC card

  Lexar High-Performance 633x V10 microSDHC card

  $17 at Amazon
• Best V30 SDXC card

  Samsung Evo Plus

  $20 at Samsung
• Best V60 SDXC card

  SABRENT Rocket V60 UHS-II SDXC card

  $50 at Amazon
• Best V90 SDXC card

  Kingston Canvas React Plus SDXC UHS-II V90 card

  $80 at Amazon

The SD Association also introduced the SD Express specification in 2018 that uses up to two PCI Express lanes to provide a huge increase in throughput. The SD and microSD cards with SD Express aren't readily available on the market, though, and it remains to be seen whether that changes anytime soon. You can easily identify the speed class of the card by looking at the logos on the card itself. Here's a quick look at the SD card speed logos to look for while purchasing an SD or a microSD card:

If you come across an SD card with no symbol, then it was most likely produced before the speed class rating was introduced. Such older SD and microSD cards belong to class 0, which means they may be slower than even a class 2 card.

Counterfeit products and brands to avoid

A surprising number of fake SD cards are making rounds on Amazon and other marketplaces, and there's a good chance that you'll come across one of these while shopping for a good SD or a microSD card. There's no way to tell whether the card you're buying is a counterfeit product until you receive it in hand and test it, but a shocking good deal on a branded memory card from a non-reputable seller is often a telltale sign it's fake. I highly recommend checking the reviews and reading a bit about the seller buying from them.

Try not to cheap out on brands, and stay clear of any SD cards that come from unknown manufacturers. There's a good chance that they're fake, and they'll likely give up on you very soon or won't perform as advertised. If you suspect you have a counterfeit SD card, then consider using free tools like H2testw and F3 to test. If you're unsure of the brands to go for, then simply pick an SD card from the ones highlighted in this guide to ensure you're getting the right product.

Closing thoughts

There is no shortage of SD cards on the market, but it's recommended that you stick with options from reputed brands like SanDisk, Lexar, Samsung, and more. Also, if you're unsure of which SD card to buy for your device, then consider checking out its specification sheet to find the recommended parts. It's important to pick an SD card with the right speed class, size, and capacity, so feel free to explore all the options to find the right one for your needs.