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We bought over 20 of the best memory cards on the market, then whittled the selection down to the top 12 to test side-by-side. We measured how quickly these cards transfer a range of file types and sizes and tested their abilities to keep up with basic and advanced tasks when employed by a modern digital camera. We tested high-performance options for taxing tasks like shooting rapid-fire RAW images or capturing 4K video. We also tested inexpensive, reliable options that pair well with security cameras and other less demanding devices. However you plan to use your new memory card, our tests will help you find the right option for your needs.
Max measured write speed: 234 MBps | Available sizes: 32 to 256 GB
REASONS TO BUY
Fast large file write speed
Impressive small file write speed
Solid read speed
REASONS TO AVOID
Expensive
Top speeds require UHS-II hardware
If you often record lengthy 4K or 6K videos or rapid-fire RAW photos, a UHS-II card like the Lexar Professional 2000x UHS-II is your best bet, if your equipment is compatible. UHS-II cards have two rows of shiny electrical contact points, increasing the maximum possible transfer speeds from 104 MBps to 312 MBps (megabytes per second). When you need to move a lot of data quickly, that's an enormous advantage. In our tests, it took less time to write a large, 5 GB file onto this card than any UHS-I card, and it is comparable to the other USH-II options. When we transferred 2 GB of smaller files like documents and spreadsheets, this card posted the fastest speeds in the test. You can also purchase a 2000x with up to 256 GB of storage, the most that we've seen on a UHS-II option.
Despite reading large files very quickly, the Lexar Professional 2000x UHS-II has some of the slowest small file read speeds we tested. Since reading files involves pulling them from the card onto your device, they are considered less critical than write speeds, which count when capturing content while taking photos or filming. If it matters to you, check out the Transcend UHS-II, which has less memory but is a faster reader and costs less. Conversely, this memory card is not exactly budget-friendly. Before investing in a card with higher performance and memory, we recommend double-checking your device and card reader to ensure they are UHS-II compatible. Without the appropriate hardware, either card will be limited to UHS-I speeds. Price point and limitations aside, either card is likely worth it if it'll save you precious time every day.
The Lexar Professional 2000x UHS-II is one of the highest-performing memory cards we've tested.
Credit: Ross Patton
UHS-I versus UHS-II — UHS stands for an ultra high-speed bus. The bus, which is the line of shiny gold metal on the back of the memory card, transports (or drives) your data back and forth from the card to your devices.
A UHS-I card has one bus, or one row of metallic contact terminals, and is capable of transfer speeds up to 104 MBps.
UHS-II cards have two, which makes them capable of transferring data at speeds up to 312 megabytes per second (MBps), which is especially important if you want video quality of 6K or more.
If your card reader or camera can't read both rows, you won't be able to take advantage of their lightning-fast data transfer. Luckily, they are backward compatible and your device should be able to use them, just at UHS-I speeds. Do some Googling to see if your equipment can take advantage of the newer tech.
You may be thinking that it's worth using a UHS-II card with a UHS-I device as long as you have a UHS-II reader to improve transfer speeds. We're skeptical that it would be worth the extra cost, and UHS-II cards tend to offer less memory storage.
Max measured write speed: 106 MBps | Available sizes: 32 to 512 GB
REASONS TO BUY
Relatively fast transfer speeds
Solid price-to-performance ratio
Durable construction
REASONS TO AVOID
Fast only for UHS-I options
The SanDisk Extreme Pro UHS-I is an excellent option that provides more than enough speed and storage for most memory card users. It offers impressive large file write speeds, logging a high speed of 106 MBps in our tests. That should be enough for serious photography hobbyists who capture RAW images and record in 4K. You can also rest easy knowing that the Extreme PRO is sufficient for devices like camera drones that require higher-speed cards to function. Notably, it achieves these speeds while avoiding the high price tags of the fancier UHS-II cards.
If price is a concern, there are less expensive options available. That said, with this card, you're buying peace of mind that a lagging card won't let you down at your next photo shoot. This water, shock, x-ray, and temperature-proof card is also impressively hardy. If you're looking for a reasonably priced card that performs consistently in a range of conditions and can store up to 512 GB of data, the SanDisk Extreme Pro UHS-I is a top choice. If you don't need to capture large files and prefer snapping jpeg photos, the SanDisk 32GB Ultra SDHC described below could be the one for you.
The all-around performance of the SanDisk Extreme Pro will be more than suitable for most photographers.
Credit: Jason Peters
Reading and Writing Writing speeds refer to how quickly a device like your camera can transfer data onto your card while taking photos or recording video. Reading speeds reference how quickly your device can pull data from the card. As a result, writing speeds are often more important to folks like photographers, who need the highest performance in the field and who can afford to wait a little longer for files to download onto their computers after the fact.
In contrast, gamers who want a MicroSD card to expand the memory of their Nintendo Switch will focus more on read speeds, which control how quickly games and content will download from the card.
Max measured write speed: 101 MBps | Available sizes: 32 GB to 512 GB
REASONS TO BUY
Lots of storage options
Easily handles 4K video and RAW images
Exceptional small file write speed
Great large file write speed
REASONS TO AVOID
More expensive than basic microSD cards
Larger storage options available
The memory cards in Kingston's Canvas line consistently shine in our tests, and the microSD version is no exception. That's why the Kingston 128GB microSDXC Canvas Go Plus is our top recommendation if you're in the market for a compact card. We measured a large file write speed of 101 MBps for this UHS-I model, which is fast enough to capture high-quality imagery. Not only is this card suitable for large files — when it comes to writing small files it is the fastest microSD card that we've tested to date, giving it a great overall average write speed.
The Kingston 128GB microSDXC Canvas Go Plus is a little pricier than the average microSD card, especially if you opt for more storage capacity. Still, we think its performance is worth the money, especially considering you're buying back your time. It also includes an SD converter, conveniently allowing you to use it in standard or micro SD card slots. The SanDisk 64GB Extreme MicroSDXC is another excellent microSD card with slightly slower average writing speeds but more generous storage options.
The Kingston Canvas Go Plus is our go-to for a microSD that can handle just about everything you can throw at it.
Max measured write speed: 224 MBps | Available sizes: 32 to 64 GB
REASONS TO BUY
Top-notch write speeds
Impressive average read speed
Affordable for a UHS-II card
REASONS TO AVOID
Less available memory
UHS-II hardware limitations
If you're shopping for a UHS-II memory card on a limited budget, we highly recommend the Transcend UHS-II. Its performance is on par with pricier cards, and it recorded some of the fastest large and small file write speeds we tested. It also reads small files faster than several more expensive options and didn't lag too far behind when reading our large, 5 GB test video. We appreciate that this card includes a clear plastic protective case — an extra that many manufacturers choose not to include with the purchase.
As with other UHS-II memory cards, the Transcend must be used with the appropriate hardware (for example, cameras and SD card readers) to access its maximum speeds. Otherwise, it will function at UHS-I levels. We tested the 32 GB version of this card. There is a 64 GB version, but that's as far as it goes. Since other UHS-II cards offer up to 512 GB and UHS-I cards can provide a full terabyte (TB), we're not impressed. Although this card has less memory than most, its lightning-fast transfer speeds make it our top pick for an affordable UHS-II model. To save even more, and gain much more storage capacity (up to 512 GB), check out a UHS-I option like the SanDisk Extreme Pro UHS-I.
The Transcend UHS-II quickly writes and reads large files and won't wreck your bank account.
Max measured write speed: 37 MBps | Available sizes: 32 to 128 GB
REASONS TO BUY
Inexpensive
Fast enough read speeds
REASONS TO AVOID
Slow write speeds for advanced tasks
If you have relatively basic memory card needs — like recording 1080p videos or taking jpeg photos — you probably don't need to pay for top-of-the-line storage capacities or extreme data transfer speeds. That's where the SanDisk 32GB Ultra SDHC comes in. It provides enough firepower for common tasks while keeping costs significantly lower than faster cards. Like most of their products, SanDisk claims that this card can handle shock forces, water, and temperature extremes and that it won't be affected by the X-ray machines at the airport.
Like most things, the lower price point comes with tradeoffs. For instance, the speeds aren't sufficient for some advanced camera drones. That said, they're adequate for most uses. If you like to shoot burst images in RAW, the speeds will also slow you down. Still, we had no issues recording 4K video with this card. As long as you're not planning on completing data-intensive tasks, the SanDisk Ultra SDHC provides reliable performance at a low price. Really though, the superior SanDisk Extreme Pro UHS-I isn't that much more expensive and is well worth the extra few dollars.
The SanDisk Ultra balances performance and price quite well.
Credit: Jason Peters
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How We Test Memory Cards
After researching the best memory cards on the market and buying the top tier to test head-to-head, we created protocols to compare and contrast their performance. We measured their write and read speeds in a range of scenarios, including when plugged into a computer and used in a camera. For each test, we transferred both large movie files and folders full of photos, documents, and spreadsheets to assess their ability to capture and transfer high-quality video, still imagery, and scattered files. All told, these memory cards undergo up to 60 individual tests in the lab.
We break down our overall score into four key metrics:
Large File Write Speed (25% of overall score weighting)
Small File Write Speed (25% weighting)
Average Read Speed, for both large and small files (25% weighting)
Storage Range (25% weighting)
Why Trust GearLab
The design of our memory card testing process is informed by the expertise of our in-house photographers, Laura Casner and Jason Peters. Combined, they have multiple decades of professional photography and videography experience and have burned through hundreds of memory cards throughout their careers. Senior review editors Max Mutter, Ross Patton, and Clark Tate have tested and reviewed many data transfer devices. Most recently, they tested USB flash drives and external hard drives and have tested over 100 devices that utilize memory cards, such as drones, security cameras, and dash cams. Clark is also a photographer and podcast field producer who has used these cards in a range of weather conditions. The detailed results below summarize the performance of 12 of the best memory cards on the market.
The Transcend UHS-II is one of our top-scoring models when it comes to writing large files.
Despite the cards looking similar, we found a large degree of variability in terms of overall performance.
Many modern computers only have MicroSD slots or no card reader at all.
Analysis and Test Results
Write speed refers to the rate at which data can be collected and written onto a memory card for storage. It's often the most important factor differentiating memory cards since many people use them to capture photos, audio, and video in the field. Faster write speeds translate to capturing high-quality video and images without any buffering, lagging, or impaired image quality, so you don't lose a single action frame.
We separated our write speed tests into two categories — large files and small files. Large-file write transfers test each card's ability to record video. In contrast, small-file write speed indicates a card's prowess in taking many still images in rapid succession. We also measured large and small file read speeds, or how quickly a card can upload existing files to your computer. These are important if you want to use a card to expand your device's memory, or store games on them for your Nintendo Switch.
A Word About Bus Interfaces
The primary difference between a UHS-I and a UHS-II memory card is that a UHS-II has an additional row of terminals, allowing for substantially faster data writing and marginally faster data reading. However, your devices must have the appropriate hardware to be compatible. Otherwise, a UHS-II will be limited to UHS-I speeds. Professional photographers and videographers primarily the newer, faster UHS-II cards.
The primary difference between a UHS-II (left) and a UHS-I (right) interface is that the UHS-II has an extra row of contact terminals.
Credit: Ross Patton
What's the Best Value?
To figure out how much you need to spend on a memory card, you'll first need to define how you're going to use it. If all you require is write and read speeds fast enough to handle smaller jpeg files or 1080p video, there is no reason to invest in anything other than the SanDisk 32GB Ultra SDHC, which is our favorite option for our trail camera test.
Our favorite UHS-I memory card, the SanDisk Extreme Pro UHS-I, is very reasonably priced considering its overall performance and solid storage capacity. For those needing the fastest write speeds on the market to capture professional-grade RAW photo files and 4K or 6K video, you'll need a UHS-II card. The Transcend UHS-II is our budget-friendly choice, but it only offers up to 64 GB of space. If you're shooting an event or producing in the field, you're likely to need a top-dollar card like the Lexar Professional 2000x UHS-II. If you're drone or other requires a MicroSD card and don't mind paying a few more dollars, the SanDisk 64GB Extreme MicroSDXC is the way to go.
There are a lot of tiny numbers and letters on SD cards. Here's what they mean.
Credit: Clark Tate
Large File Write Speed
We tested large file write speed in two ways. First, we transferred a 5 GB, 1080p video file onto each card using the same SD card reader and timed the transfer. This test allowed us to measure how quickly each card could record the exact same video file. Transferring large files is the easiest task for cards, so this speed represents the maximum functional write speed.
We then conducted a pass/fail test, putting each card into a camera, recording five minutes of 4K video, and then reviewing the footage for any dropped frames or pixelation. All of the cards in the review passed this test. To double-check our measurements, we used a desktop Disk Speed Test application by Blackmagic Design. The tested maximum speed values were in line with the Disk Speed Test results.
We used Blackmagic Design's Disk Speed Test as an outside source for comparing our results.
Credit: Ross Patton
The Sony Tough High Performance SDXC UHS-II transferred large files in the least amount of time, with an impressive speed of 252 MBps. The SanDisk Extreme Pro UHS-II is a close second with a speed of 246 MBps. The Lexar Professional 2000x UHS-II and Transcend UHS-II aren't far behind, attaining a maximum write speed of 234 and 224 MBps, respectively.
You'll notice that all of the fastest cards tested are UHS-II since they have around twice as many transfer terminals as single bus cards. They also have V90 video speed ratings. According to B&H Photo Video, that means they are suitable for shooting video in 120 frames per second (fps) or more.
The fastest of the UHS-I cards we tested is the SanDisk Extreme Pro UHS-I. It reached 106 MBps in our test, offering plenty of speed for hobbyists. The SanDisk 64GB Extreme PLUS SDXC and PNY 128GB Elite-X SDXC aren't too far behind, reaching max speeds of 82 MBps each. The best microSD cards we've tested also fall within this mid-tier category when it comes to write speeds. The Kingston 128GB microSDXC Canvas Go Plus, SanDisk 128GB MicroSDXC for Nintendo Switch, and SanDisk 64GB Extreme MicroSDXC fell in at 101, 97, and 83 MBps respectively. These cards have a V30 video speed class, which can handle up to 60 fps of 4K video.
Performing admirably in every test, the Extreme Pro is a great option.
Credit: Jason Peters
There's a significant dropoff in speed after that, but all of the cards tested passed our 4K recording test, indicating they can all handle even taxing large files.
Small File Write Speed
To test small file transfer rates, we loaded the same two-gigabyte folder full of more than 4000 photos onto each card, timing the transfer each time. This test provided a baseline speed measurement for how quickly each card could ingest multiple photo files.
We then tested this speed in-camera, shooting RAW images in burst mode until the cards started to bog down. While doing so, we recorded each camera using a microphone and basic audio software. The shutter clicks showed up as large spikes in the recorded soundwaves, allowing us to visually assess how quickly each card was able to process images and time how long it took them to get bogged down. These in-camera measurements lined up almost perfectly with the results from our first test.
The Lexar Professional 2000x UHS-II and Transcend UHS-II lead the pack with small file transfer speeds of 54 and 53 MBps, respectively, making them ideal for those working with many smaller files. This speed allowed it to keep our camera's shutter moving at full speed in our RAW burst shooting test. This is more than enough speed for almost any photography application.
Here at GearLab, we buy all of our products from the same retailers as our readers to eliminate bias.
Credit: Ross Patton
After this, there is a steep dropoff in performance. The SanDisk 32GB Ultra SDHC is the closest competitor at a speed of only 37 MBps. Beyond this point, the cards got progressively slower. But in a practical sense, the differences were relatively small.
Lackluster performance in our file transfer test translated into decent in-camera performance, as the very slowest cards could still shoot four seconds of full-speed burst RAW images before slowing down. Unless you're a professional, you may not notice their lack of speed in everyday photography and film projects.
Measuring RAW image burst speed using audio recordings. Faster cards kept clicking continuously (above) while slower ones stopped and stuttered (below).
Average Read Speed
Read speed is the rate at which a card can pull files from its memory and transfer them to another device. We measured both large and small file read speeds by offloading the same video and photo files from our previous tests onto a computer and timing the transfer. We then calculated an average rate of megabytes per second. We put less emphasis on read speeds since they often have more bearing on file organization than content capture. If you're looking for a card to extend the memory of your tablet or gaming console, they may matter more to you.
For the most part, read speeds are faster than write speeds, and the cards read single, large files faster than many small ones. And, of course, USH-II cards are the fastest. If you need a card that can read files in a flash, it's likely worth spending the extra money to upgrade to a UHS-II card. Keep in mind though, not all devices have the hardware required to read both rows of UHS-II contact points, so you'll also need a fancier card reader or camera to make the additional cost worthwhile.
The Sony Tough High Performance SDXC UHS-II and SanDisk Extreme Pro UHS-II posted the fastest large file read speeds at 273 MBps. The Lexar Professional 2000x UHS-II and Transcend UHS-II weren't far behind at 234 and 220 MBps, respectively.
The various types of cards have different numbers of terminals.
Credit: Ross Patton
As for the UHS-I devices, the SanDisk 64GB Extreme SDXC and SanDisk Extreme Pro UHS-I clocked impressive numbers at 167 and 164 MBps. The three microSDs in the review kept up. Most notably, the SanDisk 128GB MicroSDXC for Nintendo Switch posted speeds at 168 MBps. Since this card is often used to store saved games, it's handy that your Switch will be able to download them from the disk quickly. The SanDisk 64GB Extreme MicroSDXC would serve as a good alternative at 164 MBps.
The other cards read large files at around 90 MBps and average speeds around 70 MBps. It's worth noting here that, of the UHS-I files the SanDisk Extreme Pro UHS-I offers a solid average speed across the board.
At first blush, the PNY Elite-X SDXC's 128 GB of storage claimed 100 MBps transfer speeds seem more appealing than the SanDisk Extreme PRO SDHC's 32 GB and 95 MBps speeds. But the SanDisk outperformed the PNY in our tests.
Credit: Clark Tate
Storage Range
Finally, we looked at the potential storage range for each card, which ranges wildly from 32 to 1000 GB, which is equal to 1 terabyte (TB). Memory cards aren't meant for long-term storage. If you're capturing high-quality photos and videos, you'll want to download them and back them up on an external hard drive as soon as possible. Then you clear and reformat your memory card to reuse it. With this in mind, think about how much data you'll need to use at a time, in a single photo session for instance, and choose an SD card accordingly.
What's with all the SDs? — The SD in SD card stands for secure digital. All the letters that come after that refer to how much memory, or storage space, a card has.
SD - A plan old standard SD card will have up to 2 GB of memory
SDHC - Is a High Capacity card that can hold between 2 and 32 GB
SDXC - An Extreme Capacity card with between 32 GB and 2 TB
SDUC - These Ultra Capacity cards hold between 2 and 128 TB
When it comes to storage space, the UHS-I cards we tested take top honors. Of those, the microSD cards offer some of the best memory capacity in the test. You can choose between seven storage options when you purchase the SanDisk Extreme MicroSDXC, and it's the only option we tested that grants up to 1 TB of storage space. So, even though doesn't have the fastest write and read speeds, if you don't need rapid-fire shutter speeds or offer 60 frames per second in your film sequences, this is a great option for anyone who needs to capture a long photo shoot.
A 32 GB memory card will capture about 800 RAW photos if they are around 40 MB each.
Credit: Clark Tate
The Kingston 128GB microSDXC Canvas Go Plus and full-size SanDisk Extreme Pro UHS-I both balance impressive storage capacity, up to 512 GB with consistently solid read and write speeds. They are excellent, well-rounded options. The PNY Elite--X SDXC card also offers 512 GB but is slower to read and write all of that data. Since it costs about the same as the SanDisk Extreme Pro UHS-I, we can't think of a good reason to recommend it.
Most microSD cards include an adapter, allowing them to be used as a standard-size memory card.
Credit: Clark Tate
None of the UHS-II cards offer storage over 256 GB. Both the Lexar Professional 2000x UHS-II and SanDisk Extreme Pro UHS-II provide the most for this category at 256 GB. If a RAW photo is around 40 MB, that's around 6,400 photos. That may be plenty for your needs. The Transcend UHS-II card offers much less, topping out at only 64 GB or 1,600 RAW photos. That could still be more than enough for your needs.
We tested these SD and microSD cards head-to-head to find the best options for your needs.
Credit: Clark Tate
Conclusion
As cameras, drones, and smart devices become increasingly ubiquitous, the need for memory cards and their reliable, solid-state data storage is growing. Frustrating, most memory cards look nearly identical, with only obscure naming techniques, arcane statistics, and jargon-filled advertising to help you choose one over another. Our review will help you cut through the confusion to help you find the right memory card for your needs and budget.
With so many advancements in the latest electronics gear, it can be hard to keep up with what's current and what's now obsolete. We've tested tech items like top-rated drones and trail cameras to help uncover the best products.
