After eight hours of research and 15 hours of testing, we determined that the 32GB Samsung EVO is the best microSD card for phones and tablets. It has fast sequential and random read/write speeds, the latter of which are important if you’re using this card as additional storage for your mobile device.
The Samsung EVO has fast random read and write speeds for storing and retrieving app data, and is also fast enough to handle 1080p video recording. However, for those using a GoPro Hero 3 Black Edition, we think the 64GB SanDisk Extreme is the best option because it’s the most affordable and lots of Amazon reviewers report back that it’s a reliable option.
The Samsung EVO card is faster than our previous pick, the 32GB SanDisk Ultra, and also $6 more expensive. We think it’s worth it for the faster 4KB random and sequential speeds across the board. Still, there are no major flaws with the SanDisk Ultra, and it’s a decent option if our (new) main pick is sold out.
Who should(n’t) buy this
Not many devices use microSD cards these days. Most current smartphones — iPhones, Windows Phones, and even flagship Android phones, like the Moto X and the Nexus 5 — rely on internal storage only, and don’t have microSD slots. A few devices like the HTC One M8, the Samsung Galaxy S5, and the Barnes & Noble Nook do support microSD, but also have internal storage. MicroSD slots are also common in Android and Windows tablets. It’s important to check that you need one before you spend the money.
All microSD cards come with an adapter to use in a full-size SD card slot, but that doesn’t mean you should use a microSD card in an adapter as a replacement for an SD card.
For security reasons, as of Android 4.4, Google has limited what parts of the microSD card third-party apps can access. Instead of having read and write access to anything stored on the card, apps can now only modify their own dedicated folders. Android Central has a good explanation of what this means. The short version: The update will break some apps that are programmed to access parts of the SD card they’re no longer allowed to, until those apps are updated to work within Google’s new parameters. For the 5.3% of users on Android 4.4 devices, camera apps are only allowed to record and modify images and video within their dedicated folders. No other apps can modify these files unless you root your phone and roll back the update. The benefit of the update is that malicious apps no longer have carte blanche access to all the data on your microSD card.
All microSD cards come with an adapter to use in a full-size SD card slot, but that doesn’t mean you should use a microSD card in an adapter as a replacement for an SD card. As a general rule, microSD cards are much slower and less cost effective than their full-size counterparts. Our recommendation, the 32GB Samsung EVO, has sequential read and write speeds of 46.573 MB/s and 16.047 MB/s, and costs $27. For comparison, the 32GB SanDisk Extreme Plus is way faster (92.4 MB/s read and 60.7 MB/s write) and only costs $13 more.
How we picked which microSD cards to test
The most important features in a microSD card are speed, price, reliability, and warranty.
The most important features in a microSD card are speed, price, reliability, and warranty. In a phone or tablet, a microSD card’s 4KB random read and write speeds are paramount because, in most cases, apps save data in small chunks scattered across the card. Sequential speeds are less crucial than 4KB speeds, but are still significant. Sequential write speed matters when shooting photos and video directly to the card, and sequential read speed determines how long it takes to transfer files from your microSD card in bulk (to your computer, for example).
If you need a microSD card for your Sony X10, Canon Powershot N, Samsung Galaxy NX, Nikon S810x, GoPro, or other camera — and we mean a microSD card, not a microSD card in an SD card adapter — then sequential read and write speeds trump 4KB speeds in importance.
A lot of Class 10 microSD cards have terrible 4KB random write speeds, as you can see from this collection of microSD benchmarks taken with CrystalDiskMark and these2011 and 2014 tests by Tom’s Hardware. According to some users’ tests, the 4KB random write speeds on some cards tank from 1-2MB/s down to .006. You don’t want one of those cards for your smartphone or tablet.
Even though a lot of Class 10 microSD cards have this problem, you don’t want a lower class of card. A Class 10 rating denotes sequential read and write speeds of at least 10MB/s, and is given to cards rated to shoot 1080p video. (Click here for a more detailed explanation of microSD card speed classes.) Without a Class 10 card, you’ll encounter problems recording video to your microSD card.
Keeping these criteria in mind, we researched microSD cards from manufacturers like SanDisk, Lexar, Samsung, and others, paying special attention to new models that have been released since our last update in late 2013. We also explored benchmarks byTom’s Hardware and forum users to narrow our list down to three contenders. Then we ordered the SanDisk Ultra, Samsung EVO, and Transcend Premium and tested them ourselves.
We tested each card’s sequential and random read/write performance in a Google Play Edition Samsung Galaxy S4 using A1 SD Bench. You can read more about the benchmark and how it works at the A1:dev website. We also ran CrystalDiskMark, a benchmarking program designed to test sequential and random read and write speeds on solid-state storage.
Using a USB 3.0 card reader in a USB 3.0 port, we timed a couple of file transfers—a 7.07GB folder of photos and a 1.68GB HD video—from start to finish, running each transfer three times and taking the average to rule out performance hiccups. Between each test, we cleared the cards and reformatted them using the recommended utility from the SD Association to stabilize performance. It’s important to test SD cards via USB 3.0 to prevent bottlenecks, since USB 2.0 tops out around 33 MB/s and the cards we’re testing are faster than that.
The Samsung EVO is the fastest micro SD we found for the money in addition to having a lengthy 10-year warranty and being treated to withstand all types of environmental threats.
The 32GB Samsung EVO is the best microSD card for most people’s smartphones and tablets because of its comparatively speedy 4KB random read and write speeds, snappy sequential read and write speeds, and ten-year limited warranty. It’s a little more expensive than our previous pick, but it’s made by a reliable manufacturer and is the fastest you can get without spending a lot more money, which we’ll address in the “Using a GoPro Hero 3?” section.
This edge in practical use means that the Samsung EVO will indeed offer the fastest experience in real-world situations.
We tested the 16GB model of the Samsung EVO, which should be identical to the 32GB model in all aspects but capacity. In our tests, the Samsung clocked 4KB random read speeds of 5.844MB/s and write speeds of 1.066MB/s in the CrystalDiskMark test. The 32GB SanDisk Ultra’s read speed was slower at 4.117MB/s, but its random write speed was a little faster at 1.276MB/s. However, in the A1 SD Bench test run in an actual phone, the Samsung card was much faster, measuring 12.457MB/s random read and 2.047MB/s random write compared to the SanDisk’s 8.317MB/s read and 1.203MB/s write. This edge in practical use means that the Samsung EVO will indeed offer the fastest experience in real-world situations.
As you can see in the chart above, both the Samsung EVO and SanDisk Ultra were about on par in sequential read speeds, but the Samsung had faster sequential write speeds in our CrystalDiskMark and Android tests. The SanDisk had faster read times in our file transfer tests — taking 22.33 seconds to read a large HD video compared to the Samsung’s 29 seconds — while the Samsung EVO pulled ahead in write speeds.
MicroSD cards are more durable than other storage solutions, such as hard drives, and can survive being bumped around and dropped (though they are tiny and quite easy to lose track of). The Samsung EVO is rated to survive up to 24 hours in salt water, withstand temperatures ranging from -13ºF to 185ºF, resist 10,000 gauss of magnetic field, endure the equivalent pressure of being run over by a 1.6 ton truck, and be immune to airport X-rays.
We tested the 16GB model of the Samsung EVO, but the 32GB one is more cost effective.
The Samsung EVO comes with a ten-year limited warranty. It’s not as long as the SanDisk Ultra’s lifetime limited warranty, but the SD Card Association says most SD cards have a lifespan of about ten years with “normal usage,” so Samsung’s warranty is plenty long enough.
Who else likes it?
The EVO, part of Samsung’s new line of microSD cards, was released on April 7th, 2014. As of this time there are few, if any, reviews from Amazon users and reputable sites. That said, we tested the card and were satisfied with its speed and quality, and we’ll update here if and when more reviews come in.
Flaws but not dealbreakers
The 32GB Samsung EVO is $5 more expensive than our previous pick, the 32GB SanDisk Ultra, but it’s worth it for faster 4KB random and sequential speeds across the board. The 64GB Samsung EVO is the cheapest per gigabyte of the Samsung EVO models, but most people don’t need that much space. If you do, feel free to step up to the higher capacity model, but make sure your device has SDXC support before you buy.
Our previous pick is $6 less than the Samsung EVO (and duly a bit slower), but comes with a lifetime warranty.
Our previous pick, the 32GB SanDisk Ultra, is still a great card, and is worth picking up if the 32GB Samsung EVO is out of stock. It comes with a lifetime limited warranty, is a bit slower than the Samsung, and costs $6 less than our recommendation. The SanDisk Ultra has a 4.4 star rating on Amazon with a whopping 12,166 reviews.
Using a GoPro Hero 3?
The SanDisk Extreme is recommended by GoPro, gets rave reviews by users, and is $30 cheaper than the competition.
Shooting 4K video on the GoPro Hero 3 is one of the most demanding uses for a microSD card, and, in theory, requires a constant sequential write speed of 5.6 megabytes per second. Any Class 10 card would theoretically work, but some don’t, so GoPro has a list of very specific microSD card recommendations for its cameras. According to their current list, any Class 10 card — including both our pick and runner up — will work with the Silver and White editions. For the Black Edition, GoPro recommends theSanDisk Extreme, Lexar 600x, Lexar 633x, or a Delkin.
Of these, we’d recommend the 64GB SanDisk Extreme because it’s more than $30 cheaper than either of the Lexar options and has a flood of positive Amazon reviews stating that it works with the GoPro Hero 3 Black Edition.
We eliminated any cards without Class 10, UHS-1 ratings — like the Patriot andADATA cards mentioned in our last update — since those aren’t ideal for recording 1080p video (if your device can do that) and have slower sequential speeds, which slow down transfers.
Of the microSD cards we tested, the 32GB Transcend Premium had by far the fastest sequential read and write speeds. But when we put it in a phone and tested its practical 4KB random write speeds, it measured less than half the speed of our pick at 0.583MB/s.
The Kingston Class 10 UHS-1 card is quoted to have sequential read speeds of up to 30MB/s, which is slower than our pick. It has 46 one-star ratings out of 171 total Amazon reviews, and many reviewers complain of slow speeds and issues using the card in smartphones.
The Toshiba Class 10 UHS-1 microSD card is also quoted to have slower read speeds of up to 30MB/s, but is only $5 cheaper than our pick and comes with a shorter, five-year limited warranty.
The Toshiba Exceria microSD is quoted at 95MB/s read and 30MB/s write, but the 32GB model is difficult to track down on Amazon or Newegg from a reputable seller.
Our previous recommendation for GoPro users, the Lexar 300x, is no longer recommended by GoPro and has been replaced by the newer, faster 600x model, which we addressed above.
The previous version of the Samsung Pro — a black card with grey and white lettering — has been discontinued and replaced with a new model — a grey and white card that now says “PRO” on the label — that’s also called the Samsung Pro. The 32GB and 64GB models of the new Samsung Pro cost $40 and $70 respectively, and our less expensive pick will serve most people just fine.
The SanDisk Extreme Plus is a step above and beyond even GoPro’s recommendation for its Hero 3 Black Edition camera, and most people don’t need to shell out $40 to $75 for a 32GB or 64GB microSD card.
The PNY High Performance microSD card only costs $20, but Tom’s Hardware found that it has poor 4KB random write speeds of 0.43MB/s.
Sony’s Class 10 microSD card is inexpensive and may have decent speeds, but only comes with a one-year limited warranty compared to the Samsung EVO’s ten years and the SanDisk’s lifetime limited warranty.
A note on microSD card classes
We only looked at Class 10, UHS-1 cards, and tried to find the ones with the best 4KB random read and write speeds. It’s a large category—and current card speeds stretch way above the Class 10/UHS-1 write minimum of 10 MB/s—but is the bare minimum for shooting 1080p video, and any additional sequential speed makes for faster file transfers.
…any additional sequential speed makes for faster file transfers.
The SD Association recognizes standardized speed classes for SD and microSD cards based on their minimum guaranteed speeds. Speed Classes 2, 4, 6, and 10 denote the minimum write speeds in MB/s: a Class 2 card has minimum write speeds of 2 MB/s, while a Class 10 card has a guaranteed minimum of 10 MB/s. Of course, many cards have speeds far beyond 10 MB/s, so there’s a limit to how useful those speed ratings are.
There are two Ultra High Speed classes above Class 10: UHS-1 cards are recommended for 1080p video recording and also indicate read/write speeds of at least 10 MB/s, and the recently introduced UHS-3 standard is ideal for 4KB video recording — which isn’t yet prevalent in smartphones — and designates minimum performance of 30 MB/s. You can read more about how to recognize different card speeds at the SD Association website. Many UHS-1 cards also carry Class 10 ratings.
If you get a card that’s slower than Class 10, you won’t be able to record 1080p video on the microSD card. Even if your current phone can’t shoot 1080p, your next one will, and getting a Class 10 UHS-1 card makes the most financial and practical sense at current prices.
If you want a larger card than the 32GB model we recommend, be sure to check that your device supports SDXC (extended capacity) cards. The standard was introduced in 2009, so most devices support it, but confirm before you buy.
Frustration-free packaging and counterfeit cards
When buying a microSD card from Amazon or any other retailer that provides packaging choices, be sure to select the original (not frustration-free) packaging and buy from a reputable seller. There’s a pretty large market for fake and knockoff cardsthat have much worse performance and aren’t covered by a warranty. The best way to guard against greymarket copies and ensure you get the product you paid for is to purchase microSD cards in the original manufacturer’s packaging from a reputable seller.
Care and Maintenance
MicroSD cards are a bit more durable than other forms of storage, but to ensure yours lasts its full lifespan, you should store it in a clean, dry, temperate location and handle it with care to avoid bending, snapping, or losing the tiny card when it’s outside of your smartphone or tablet. If you use multiple microSD cards for a camera like the GoPro Hero 3, you should invest in a dedicated case to store the cards and protect them from pressure and the elements.
Always unmount the card from your phone and turn the phone off before removing the card, and if you’re transferring files using a USB 3.0 card reader — like the inexpensive Transcend RDF5K — be sure to unmount it before removing it from your computer. Following these steps will minimize the chances of corrupting the card and losing files.
Should I upgrade?
If you already have a microSD card for your phone, tablet, or camera that does everything you need it to, there’s no need to upgrade right now. Our new recommendation isn’t leaps and bounds better than anything that’s been available for the past few years. However, if you’re having issues with the speed of your card — say, you want to shoot 1080p video and it can’t keep up — then it’s a good idea to upgrade.
Wrapping it up
The 32GB Samsung EVO is the best microSD card for most people’s phones and tablets because it has the fastest 4KB random read/write speeds of the cards we tested, is reliable, and won’t break the bank. It can handle 1080p video recording and comes with a ten-year warranty should it fail. For 4K video recording on the GoPro Hero 3, we recommend the faster, roomier 64GB SanDisk Extreme.
This guide originally appeared on The Wirecutter on 4/29/2014 and is republished here with permission.