Looking to learn about the different types of memory cards? You’re in the right place! On this page, we wade through the quagmire of terms, classifications, and types of memory cards you’re likely to need.

Finding an SD card that’s right for your use case can be surprisingly challenging. The memory card you want for a Nintendo Switch will look different to the one you use with your Sony product, for example.

By the end of this article, you should know enough to find what you need.

32GB Class 10 SDHC Flash Memory Card SD Card by Micro Center (2 Pack)

The SD Association

A quick note before we begin – the SD Association is the ‘global ecosystem’ of companies that collaborate to maintain SD card standards around the world. If you see a speed rating, classification, or some other identifier on the packaging, it was probably put there by these guys.

Understanding this association’s ratings for memory cards can go a long way in helping you find the products you need. We discuss this below.

SD Card Speed Ratings Explained

The SD Association has rallied to define universal speed ratings for memory cards over the past couple of decades. Their detailed – albeit slightly opaque – solution is to give every memory card on the market its own speed class.

This determines its overall data transfer speed, paying particular attention to the writing speed of each card. For high megapixel digital cameras and HD video recording, you’ll want to find transfer speeds that are fast enough for your projects.

4K video in particular demands very high speeds to be tolerable. If you’d like to learn more about these speed class specifications, the SD Association’s site explores the topic in detail.

Types of SD Cards

This is one of the most common types of memory cards. A secure digital card is a reliable, ‘non-volatile’ form of storage that’s used fairly universally in products for video recording and digital cameras.

If you want a storage option that’s likely to work across a broad variety of devices, SD memory cards are usually a good way to go. Watch out, though. There’s more than one type of SD card and the differences between them matter a fair bit.

What’s the Difference Between SD, SDHC, SDXC?

There are actually several different types of SD card that are worth wrapping your head around. (As if an article about the types of memory cards wasn’t already difficult to navigate!) We explain the differences below.

Secure Digital Memory Cards

This kind of memory card is best used for slower tasks that require less storage space. A decent SD card can still serve you perfectly well in the right context. It’s just that it doesn’t offer the write speed you’ll need for bigger files.

Expect a capacity between 128MB and 2GB. The default format for this kind of memory card is called FAT16.

A standard SD memory card will work with practically any device that supports the SD format.

Secure Digital High Capacity Memory Cards

This kind of memory card is a step up in terms of capacity. You’ll be able to store between 4 and 32GB on an SDHC card. If your device was made before 2008, double-check that this kind of memory card will be compatible.

Most modern devices should support SDHC. The default format for this kind of memory card is FAT32.

Secure Digital Extended Capacity Memory Cards

This kind of SD card is the ‘top of the range’ in terms of SD card capacity. It’s possible to store up to 2TB of data on one of these bad boys! For bigger projects involving large 4K videos, an SDXC card is a must!

The default format for a secure digital extended capacity memory card is exFAT.

Again, double-check the compatibility of any devices built before 2008. Otherwise, you should be good to go.

MicroSD Cards

MicroSD memory cards, as their name suggests, are a smaller version of the standard memory cards described above. They’re increasingly popular as the thickness and overall size of digital cameras continue to shrink.

You’ll need an SD card adapter to use a microSD card with some devices. These can be picked up very cheaply online.

Wi-Fi SD Cards

This kind of memory card adds a new level of convenience to your gear – Wi-Fi connectivity. With the right software and other equipment, you’ll be able to effortlessly transfer files from your memory card to your devices.

Just keep in mind that your Wi-Fi speed will determine the data transfer speed you’re able to enjoy.

Sony Memory Sticks and More

The photography giant, Sony, produces some of the best mirrorless cameras and autofocus technology available on the market. They’re also known for their proprietary memory cards and storage solutions.

Sony Memory Sticks

Sony memory sticks were developed by the company to work seamlessly with a broad range of their products. Keep in mind that buying Sony products can ‘lock’ you into their ecosystem of proprietary connectors and memory cards.

Remember that there are several different types of memory cards in this category; Sony continued to change and update the technology as it developed. Double-check the make and model of your Sony device before spending money on a new card.

These days, a lot of Sony cameras support the SD cards we discussed above which is great to see.

XQD Memory Cards

This type of memory card is available from both Sony and Lexar. They’re a new format of memory card designed to tackle the high megapixel digital cameras and 4K video files of the modern world.

If the speed class of your card matters to you, the Sony G series of cards currently offers the fastest speeds available.

Other Types of Memory Cards

We’re not done yet! There are still a few more card types of memory cards to discuss. We’ll cover compact flash memory and more – buckle up!

Compact Flash Memory Cards

These guys really could do with a rebrand – they’re actually not that ‘compact’ these days. They’re most typically found in devices that can afford the extra space that they take up. There’s a broad range of storage capacity and speed class options on offer here.

The fastest/ largest cards can handle around 260GB and 60MB/s. Depending on the digital cameras you’re using, you may need to pick up this kind of memory card.

Extreme Digital Picture Card (XD Picture Card)

This now-defunct form of memory card came with the high storage capacity needed to store bigger files in the early 2000s. If you’re using an older model of camera, this may be the type of card you’ll need to look out for.

Otherwise, an XD picture card is unlikely to be the right fit.

Memory Stick

Strictly speaking, this kind of removable flash memory isn’t a ‘card,’ but it’s worth mentioning anyway. A USB memory stick can hold more data than you might expect; the top-end NTFS cards can now hold up to 16TB!

If you need quick way to offload data from your laptop, this kind of flash memory can be a good way to go.

Choosing SD Cards and Storage Options – What to Consider

We’ve covered basically every kind of SD card and memory card you’re likely to encounter higher up on this page. In this section, we’ll explore some of the things to consider when picking up a card for your gear.

There are myriad factors that can make this process more frustrating than you might expect!


While this may sound like a no-brainer, you’d be surprised by how easy it is to buy a card that doesn’t work with your existing setup. The standards for write speeds and formats in SD cards are changing all the time.

Double-check your camera’s specific make and model against any card you’re considering. If in doubt, check the SD Associations site for guidance. Alternatively, contact your camera’s manufacturer directly.

Storage Capacity

A smaller 8GB card is going to fill up very quickly if you’re using it to store 4K video! Conversely, you’ll be wasting your money if you buy a 16GB card to store Microsoft Word documents. It all comes down to the type of work you’re doing and the file types it produces.

Our advice is to buy the highest capacity card you can afford, but don’t go overboard unless you really need to.


Ever fished out that old card from the early 2000s and tried to write data off it? Chances are, you were sat waiting for way longer than you’d like. The good news is that the latest memory cards out there come with pretty respectable speeds these days.

Our advice here is the same as with storage capacity above – buy the fastest speed class you can afford. Look out for ultra high speed II (UHS-II) SD cards if you want faster options.


If you’re regularly jumping between Windows and MacOS devices, you may want to double-check the format of the cards you’re using. In most cases, however, the most common cards are fairly universal in terms of format compatibility.

Some exceptions to this include Sony and Lexus cards which are built as proprietary solutions. If you want options that are more universal, avoid older Sony products in particular.


Many SD card options on the market come with their own little carrying case to keep them protected. Our advice is to use these as often as possible. While minor wear and tear is unlikely to be a problem, the metal contacts on most memory cards can scratch fairly easily.

The last thing you want is to have to deal with corrupt or lost files because some sand got into your kit bag and scratched up your cards!

Memory Card FAQs

In this section, we address some of the most commonly asked questions about memory cards online.

What’s the Fastest Type of SD Card?

If you’re looking for a top-range SD card that offers the best of the best in terms of write speed, look out for this identifier – ‘UHS-II‘. This Stands for ultra high speed class II. This class of SD card can handle up to a 312MB/s bus speed.

Keep in mind that depending on your device and the files you’re moving, your real-world speed may be a bit slower than this.

What’s the Best Brand of SD Card?

There’s no clear winner here necessarily. Your best bet will be to look out for speed and capacity identifiers that are in line with the SD Association’s guidelines. That said, SanDisk has a pretty good track record in the memory card space.


That about covers it – we hope you’ve found the information above helpful! Whichever card you choose for your gear, we hope it serves you well for many years to come.