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We bought more than 20 of the best memory cards available today and then whittled that selection down to the top 12 on the market for rigorous, side-by-side testing. We measured how quickly these devices could transfer different file types using a card reader and tested their abilities to perform basic and advanced tasks when used in a camera. We tested high-performance options for taxing tasks like shooting RAW images or capturing 4K video. But we also tested inexpensive, reliable options for use in security cameras and other remote devices. However you intend to use your new memory card, our testing results will help you find the perfect product for your needs and budget.
Max measured write speed: 220 MBps | Available sizes (GB): 32, 64, 128, 256
REASONS TO BUY
Very fast large file write speed
Unmatched small file write speed
Ridiculously fast small file read speed
REASONS TO AVOID
Requires UHS-II hardware to utilize highest speeds
Suppose you often find yourself recording long clips of 4K video or large quantities of RAW images in rapid succession. In that case, UHS-II cards like the Lexar Professional 2000x UHS-II are likely already in your repertoire, or at least they should be. In our large file writing speed analysis, this is one of the fastest models out there. But this card really shines when it comes to writing and reading large quantities of small files — it was the fastest model in both of these assessments.
Considering that memory cards are available for ten or twenty dollars, the Lexar Professional 2000x UHS-II is not what we would call a budget-friendly model. Before making the extra investment for higher performance, double-check that your device and card reader are UHS-II compatible. Without the appropriate hardware, this card will be limited to UHS-I speeds. Despite the price and limitations, this version is still the way to go if you're in the market for a UHS-II model and you have the need for speed.
Max measured write speed: 96 MBps | Available sizes (GB): 32, 64, 128, 256, 512
REASONS TO BUY
Fast small file read speed
Inexpensive compared to performance
REASONS TO AVOID
Slower small file write speed
Among the competition, the SanDisk Extreme Pro UHS-I is the best option for most memory card users. It offers impressive write speeds, logging a high speed of 96 MBps (megabytes per second) in our tests. This speed is enough for serious photography hobbyists who like to capture RAW images or record 4K videos. 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.
Though a bit more costly than the average memory card, it's far from expensive. The additional expense is minor, and any extra expense brings the additional speed and peace of mind that a lagging card isn't going to let you down at your next photo shoot. For those seeking a card they don't have to worry about, the SanDisk Extreme Pro UHS-I is a perfect choice.
Max measured write speed: 224 MBps | Available sizes (GB): 32, 64
REASONS TO BUY
Fantastic large file write speed
Impressive average read speed
Affordable for a UHS-II card
REASONS TO AVOID
Lackluster small file write speed
UHS-II hardware limitations
If you're in the market for a UHS-II memory card but have a limited budget, we highly recommend the Transcend UHS-II. During our assessment, this model recorded a large file write speed that is on par with cards that cost quite a bit more. Regarding read speeds, the Transcend outperformed a couple of models that are more expensive. It may be a rather small detail, but we appreciate that this version includes a clear plastic carrying case — an extra that many manufacturers choose not to include with your purchase.
The main flaw we found while testing the Transcend UHS-II is that it fell behind the other UHS-II models when writing a batch of small files. Also, as with other UHS-II versions, the Transcend requires a device with the appropriate hardware for this type of card to utilize its maximum speeds. But the card will still function at UHS-I speeds if your device does not have UHS-II hardware. One might argue that it might be worth using a UHS-II card with a UHS-I device as long as you have a UHS-II reader to improve overall workflow, but we're skeptical it would be worth the extra cost. Although this card has slower small file write speeds, the Transcend UHS-II is our top recommendation for an affordable UHS-II model.
Max measured write speed: 23 MBps | Available sizes (GB): 32, 64, 128
REASONS TO BUY
Fast enough read speeds
REASONS TO AVOID
Slow write speeds for advanced tasks
If you have relatively basic memory card needs — 1080p video recording, non-RAW photography, or similar — you likely won't need substantial storage capacities or extreme speeds. That's where the SanDisk 32GB Ultra SDHC comes in. It provides enough firepower for common tasks while keeping costs significantly less than faster cards. They cite that the card can handle shock forces, water, and temperature extremes, plus it won't be affected by the X-ray machines at the airport.
The lower price comes with some tradeoffs. While the speeds are adequate for most uses, they aren't sufficient for some advanced camera drones. If you like to shoot burst images in RAW, the speeds will also slow you down. That said, we had no issues recording 4K video with this card. As long as you're not looking to complete data-intensive tasks, the SanDisk Ultra SDHC provides a low price for reliable performance.
Max measured write speed: 86 MBps | Available sizes (GB): 64, 128, 256, 400
REASONS TO BUY
Lots of storage options
Easily handles 4K video and RAW images
REASONS TO AVOID
More expensive than basic microSD cards
We've been impressed with SanDisk's Extreme Pro line, and the MicroSD version is no exception. For those seeking a MicroSD card for pretty much any use, the SanDisk 64GB Extreme Pro MicroSDXC is our first recommendation. We measured a fast write speed of 86 MBps, making this card perfect for everything from expanding tablet or phone storage to capturing high-quality imagery. It comes with a converter, conveniently allowing you to use it in standard or micro SD card slots.
There is a cost for the performance of this card, especially if you opt for one of the higher storage capacities. The SanDisk Extreme Pro MicroSDXC is slightly more expensive than the average microSD card. However, we feel the extra expediency will be well worth the additional cost for most people.
Max measured write speed: 33 MBps | Available sizes (GB): 32, 64, 128
REASONS TO BUY
REASONS TO AVOID
Lacks performance compared to top models
A long list of devices that use SD or MicroSD memory cards do not require fast read or write speeds, such as security cameras, trail cameras, phones with memory expansion slots, and dash cams. Memory cards are an affordable and compact alternative to an external hard drive for people who like to back up their documents, such as students. If you are shopping for a memory card for any of these purposes, the Samsung EVO is a fantastic option. With a measured write speed of 33 MBps, this model is fast enough to record up to 4K video, great for photos, and quick enough for data transfer. It comes with an adapter, so you can use it in devices with larger slots or use the adapter to transfer files to devices that do not have a MicroSD slot. Best of all, the EVO is very inexpensive despite coming from a trusted brand.
If you're looking for an ultra-high-speed card for larger, high-resolution video files or a card that can quickly write and read a large volume of smaller files such as photos, the Samsung EVO falls short. This model is rated to UHS-I Class 1, while other MicroSD cards that we've tested are UHS-I Class 3. For those that have devices and readers that use UHS-II hardware, these cards will certainly be faster than any UHS-I model. Despite the technical shortcomings of the EVO, it's still a great option for those looking for an affordable and versatile model for basic tasks.
Why You Should Trust Us
To reveal the performance differences behind the near-identical faces of the memory cards on the market, we objectively measured their write and read speeds when plugged into a computer and used in a camera. For all of these tests, we used both large movie files and folders full of lots of photos to assess their ability to capture and transfer high-quality video and still imagery. All-in-all, these memory cards undergo 60 individual tests in the lab.
We break down our overall score into three key metrics:
Large File Write Speed (40% of overall score weighting)
Small File Write Speed (40% weighting)
Read Speed (20% weighting)
The design of our memory card testing process leans heavily on 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 and Ross Patton 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. The detailed results below summarize the performance of 12 of the best memory cards on the market.
Analysis and Test Results
Write speed is the rate at which data can be collected and is the major differentiating factor of memory cards. Faster write speeds translate into capturing high-quality video and images without any buffering, lagging, or impaired image quality. We separated our write speed tests into two categories: large files and small files. Large-file write speed corresponds to a 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 read speeds, or how quickly a card can upload existing files to your computer.
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 use these newer, faster versions.
The purpose of your new memory card is the determining factor relative to value. If all you require from a memory card is basic write and read speeds, there is no reason to invest in anything other than the SanDisk 32GB Ultra SDHC. For those shopping for a MicroSD on a budget, the same can be said for the Samsung EVO. If you're searching for a faster MicroSD and don't mind paying a few more dollars, the SanDisk 64GB Extreme Pro MicroSDXC is the way to go. Our favorite UHS-I memory card, the SanDisk Extreme Pro UHS-I, is very reasonably priced considering its overall performance. For those needing a UHS-II version, the Transcend UHS-II is our budget-friendly choice.
Large File Write Speed
We tested large file write speed in two ways. First, we transferred the same five-gigabyte 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 resulting footage for any dropped frames or pixelation. All of the cards that made our final cut passed the latter test.
To double-check our measurements, we used a desktop application called Disk Speed Test by Blackmagic Design. Our calculated maximum speed with every card we tested never deviated more than 10 MBps from the Disk Speed Test results.
The fastest card we tested for writing large files is the Sony Tough High Performance SDXC UHS-II, which posted an impressive speed of 250 MBps. A close second is the SanDisk Extreme Pro UHS-II with a speed of 246 MBps. Also among the fastest are the Lexar Professional 2000x UHS-II and Transcend UHS-II, each of which attained a maximum write speed of 224 MBps.
The fastest of the UHS-I models we tested is the SanDisk Extreme Pro UHS-I. It reached 96 MBps in our test, offering plenty of speed for all consumer-level tasks. The SanDisk 64GB Extreme Pro MicroSDXC and SanDisk 128GB MicroSDXC for Nintendo Switch fell in line just behind with 86 MBps, followed by the the SanDisk 64GB Extreme SDXC at 70 MBps. If you're willing to sacrifice some speed to save money, the Samsung Evo MicroSD card can write large files at 38 MBps, and it includes a standard-size SD adapter.
After this, there was a significant dropoff in speed. However, all models passed our 4K recording test, indicating they can all handle even taxing large-file tasks. If you have a device that requires a faster card or just want the peace of mind that your card won't limit your devices, you'll want to consider a card like the SanDisk Extreme Pro UHS-I that offers a solid average speed across the board.
Small File Write Speed
To test smaller 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 recording software. The shutter clicks showed up in the resulting waveforms as large spikes, allowing us to visually assess how quickly each card was able to process images, and at which point they started to get overwhelmed and bogged down. These in-camera measurements almost perfectly lined up with the results from our first test.
Leaps and bounds ahead of the pack, the Lexar Professional 2000x UHS-II offers a file transfer speed of 112 MBps, making it the ideal model for those working with large amounts of small files. The Sony Tough High Performance was the second fastest in our assessment, with a speed of 72 MBps.
After this, there was a steep dropoff in performance: the SanDisk Extreme PRO UHS-I is the closest competitor at a speed of only 51 MBps. This speed allowed it to keep our camera's shutter moving at full speed in our RAW burst shooting test for six seconds before pausing to buffer. This is more than enough speed for almost any photography application.
Beyond this point, the cards got progressively slower. But in a practical sense, the differences were relatively small. For example, the super-fast Lexar Professional 2000x UHS-II and the SanDisk Extreme Pro UHS-I were able to write our 2GB folder of photos in 19 seconds and 42 seconds, respectively. Even the slowest cards clocked in at under 90 seconds. This slow 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. Therefore, it's unlikely that you'll notice its lack of speed in everyday photography pursuits.
Read speed is the rate at which a card can transfer files from itself to another device. We measured read speeds by offloading the video and photo files from our previous tests from each card onto a computer with a stopwatch running the entire time. We then calculated an average rate in megabytes per second of the singular big file and the folder of smaller files.
For the most part, we found very little difference in read speeds, with only a couple of the high-quality UHS-II cards displaying significantly faster speeds. If you specifically need a card that can read files faster, it's likely worth spending the extra money to upgrade to a UHS-II card. But keep in mind that not all devices have the extra hardware required to take advantage of the extra speeds of UHS-II cards, so you'll also need a fancier card reader or camera to make the additional cost worthwhile.
The only model that broke the 200 MBps mark was the Sony Tough High Performance SDXC UHS-II, with an impressive average read speed of 243 MBps. The Lexar Professional 2000x UHS-II was the second fastest card for this experiment at 165 MBps, while both of the other UHS-II models in our review can read at around 160 MBps. The SanDisk Extreme Pro UHS-I was easily the fastest UHS-1 card at 119 MBps. Every other memory card that we tested reads files at an average rate that ranges from 65 MBps to 90 MBps
As cameras and smart devices become increasingly ubiquitous, the need for memory cards and their reliable, solid-state data storage has grown. However, most memory cards look nearly the same, with only arcane statistics and advertising differentiating them from one another. Our review will help you cut through all of that confusion and help you quickly find the right memory card for your needs and budget.
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GearLab is founded on the principle of honest, objective, reviews. Our experts test thousands of products each year using thoughtful test plans that bring out key performance differences between competing products. And, to assure complete independence, we buy all the products we test ourselves. No cherry-picked units sent by manufacturers. No sponsored content. No ads. Just real, honest, side-by-side testing and comparison.