A speed test comparing all the most popular UHS-II and UHS-I memory cards in the Galaxy S8 and S8+ Phones.
Use this guide to find the best memory card for your needs.
Phone Camera Specs
Processor: Octa-Core Chipset
Memory Cards: UHS-I Single Slot
| Rear Camera | Front Camera |
| Sensor: 12MP 1/2.5″ | Sensor: 8Mp 1/2.5″ |
| Lens: f1.7 | Lens: f1.7 |
| Image Stabilization: Optical | — |
| Video: 3840 x 2160p 60 fps | — |
| 35mm-Equivalent Focal Length: 26 | — |
Samsung Galaxy S8, S8+ – Amazon / BHphoto
Best Memory Cards Samsung Galaxy S10, S10+ – performance is very similar, I just tested way more cards.
Best Memory Cards For The Galaxy S8 & S8+ Phone
Unlike a lot of other sites that list memory cards for the Galaxy S8, I actually own and test them all.
There is a lot of confusion when it comes to testing SD memory cards in the Galaxy S8. Most of the benchmark software will test the emulated SD memory card which is not the real external memory card.
A1 SD allows you to test the real SD memory card. Many of the other programs will allow you to browse to find the external memory card in /storage/0000-0000 but I was then getting “access denied.” So A1 SD was my application of choice for doing these tests.
Samsung Galaxy S8 Memory Card Speed Comparison
Memory card read/write speeds were tested using A1 SD in the Samsung Galaxy S8+ using the Long-Default test with the fastest results taken out of several tests.
| Micro SD Memory Card | Read Speeds | Write Speeds |
| UHS-II – phone not capable | ||
| Sandisk Extreme Pro 64GB UHS-II | untested | untested |
| Lexar 1800x 64GB UHS-II | untested | untested |
| Lexar 1000x 64GB UHS-II | 70.88 MB/s | 35.19 MB/s |
| Delkin 64GB UHS-II | untested | untested |
| UHS-I | ||
| Sandisk Extreme Pro 64GB U3 | 72.23 MB/s | 68.48 MB/s |
| Sandisk Extreme Plus 64GB U3 | 73.25 MB/s | 66.67 MB/s |
| Sandisk Extreme 64GB U3 | 78.13 MB/s | 56.89 MB/s |
| Sandisk Ultra C10 – Old Version U1 | 38.79 MB/s | 15.80 MB/s |
| Sandisk Ultra C10 – New Version | 70.55 MB/s | 31.40 MB/s |
| Lexar 633x 64GB U1 | 67.46 MB/s | 23.54 MB/s |
| Lexar 300x 64GB U1 | 36.98 MB/s | 22.64 MB/s |
| Transcend Ultimate 633x 64GB U3 | 65.67 MB/s | 39.65 MB/s |
| Transcend Premium 400x 64GB U1 | 64.75 MB/s | 22.87 MB/s |
| Transcend Premium 300x 64GB U1 | 65.53 MB/s | 23.41 MB/s |
| Transcend High Endurance | 20.21 MB/s | 20.44 MB/s |
| PNY Pro Elite 64GB U3 | 65.15 MB/s | 64.60 MB/s |
| PNY Elite U1 | 66.11 MB/s | 28.69 MB/s |
| Samsung Pro+ 64GB U3 | 66.10 MB/s | 68.37 MB/s |
| Samsung Pro 64GB U3 | 66.99 MB/s | 62.67 MB/s |
| Samsung Pro Select 64GB U3 | 67.56 MB/s | 68.47 MB/s |
| Samsung Evo 64GB U3 | 15.16 MB/s | 20.17 MB/s |
| Samsung Evo Select 64GB U3 | 15.02 MB/s | 18.42 MB/s |
| Samsung Evo+ 64GB U1 | 63.92 MB/s | 19.35 MB/s |
| Samsung Evo Select 64GB U1 | 67.26 MB/s | 20.62 MB/s |
| Samsung Evo 64GB U1 | 37.48 MB/s | 20.62 MB/s |
| Delkin 64GB | 65.44 MB/s | 64.78 MB/s |
| Patriot 64GB U1 | 53.42 MB/s | 19.50 MB/s |
| Netac Pro 64GB U3 | 62.48 MB/s | 32.39 MB/s |
Top 3 Fastest Write Speeds – Micro SD Memory Galaxy S8 / S8+
These are the best micro SD memory cards for the Galaxy S8, S8+ at writing data.
(Tested in-phone)
Sandisk Extreme Pro
The Sandisk Extreme Pro is the fastest micro SD memory card for the Galaxy S8, S8+. Sandisk all around usually makes the best card and are a very trusted brand. Because this card is U3, it will be a great card even for future devices. – Amazon
Samsung Pro+
The Samsung Pro+ is the best micro sd memory card by Samsung that is UHS-I. In terms of performance and reliability, it’s up there with Sandisk. – Amazon
Samsung Pro Select
The Samsung Pro select is a newer card I’ve just added to the list. It’s very fast, not as fast as the other two, however, it can be found at a lot better of a price. – Amazon
Top 3 Fastest Cards Read Speed – Micro SD Memory Galaxy S8 / S8+
If you do mostly read access here are the best micro sd memory cards for S8, S8+ for read access.
(Tested in-phone)
Sandisk Extreme Pro
The Sandisk Extreme Pro also has the fastest read speeds. All around it’s the best card for the Galaxy S8 / S8+. – Amazon
Sandisk Extreme Plus
The Sandisk Extreme Plus has a great balance between performance and price. It’s a fantastic card with both read and write speeds and is comparable to the Extreme Plus when tested in the Galaxy S8. – Amazon
Sandisk Extreme
If you’re looking for the fastest sd card for read speeds in the Galaxy S8, this is it. This was the fastest card I tested for read speeds alone. It’s also a really good value between price and performance. – Amazon
Memory Cards and Brands To Avoid
The only cards that I would be cautious about would be any old cards, like the Sandisk Ultra – Old Version. That card ran very hot and its performance when testing was all over the place. In fact, avoid old versions of any card on Amazon. I think some have been labeled old even since I’ve purchased these so I’ll try to update as much as I can.
There is also Patriot and Netac Pro. I don’t know much about these brands so I wouldn’t trust them either. I actually gave one to my niece for her to use in her tablet, so I’ll know soon if there are any problems with them.
Memory Cards and Brands You Can Trust
The best all-around brand seems to be Sandisk. However, Lexar, Transcend, and Samsung are also great. It’s not uncommon for the cards made by Samsung to work best in Samsung devices. That’s the way Sony cards typically work. They may not be the fastest, but they usually are the most reliable.
Frequently Asked Questions
Will The Galaxy S8 Support 128GB and 256GB Cards?
Yes. The Galaxy S8 and S8+ support micro SD memory cards up to 256GB.
Does The Galaxy S8 / S8+ Support UHS-II Memory Cards?
While USH-II memory cards do work in camera, I see no speed improvements over standard UHS-I cards.
My Memory Card Is Slow Or Isn’t Working
There are a lot of counterfeit cards out there, especially on eBay, so make sure you buy your cards from a trusted source. If you buy on Amazon, buy from the manufacturer directly.
Sometimes cards can just be bad. It happens. Send it back for a replacement, or send it in for a warranty.
Be sure the card is clean and the connectors inside the phone are clean.
Best Micro SD Memory Cards For The Galaxy S8 / S8+ | Bottom Line
There are a lot of cards out there made by a lot of different brands. Some are better than others. A lot of the top brands like Sandisk make the fastest cards, but also the most reliable. If you’re using your phone to access your SD card a lot (like installing games on it), then it may be useful to buy one of these faster cards.
If you’re just looking for a card that you can use for storing extra photos or video, then there may be no need to break the bank, depending on your needs.
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Have you tested the uhs-ii cards with the galaxy s8?
Not yet, still waiting on getting the phone.
Bummer. I’ve had mine since 4/19… got the SanDisk uhs-ii card, but unsure if it’s being fully utilized. What benchmark can i run?
Couple things you could try, A1 SD or SD Tools. You can also see if the card slot on the phone has the extra set of teeth that match with the UHS-II cards.
Samsung with their NX1 camera shipped with UHS-II hardware, but it wasn’t until later that they released firmware to take advantage of it. So if the hardware is there and you see there are extra teeth, there could be hope that firmware offers UHS-II later if you see it underperforming right now.
Let me know if you get UHS-II speeds or not so I can update. I won’t be able to test likely until this weekend or later. Just too much stuff on my plate right now.
PCMark score. https://uploads.disquscdn.com/images/1f4c8cf98b04c80f2e7bdd5fa6146994bd28d830cc0d757f429d5f8f5b9284d3.png
Run the A1 SD benchmark a few times. There is something about that software caching the results so you need to run it a few times to get the most accurate results. PCMark seems like it’s not displaying accurate results. Based on A1 SD it looks like the phone is not utilizing UHS-II. You could also try SD Tools to confirm.
Actually it might UHS-II, The Red card on A1 SD use to be internal and the yellow was external. But if that’s the case, the internal memory seems like it’s very slow. So something seems off.
A1 SD results. https://uploads.disquscdn.com/images/eb767357d02e539324d079e9ca576cbcfd2620172ab7f15e79e4b9d3767e86e0.png
There are a few ways to test memory card speeds and there aren’t a lot of great options for Android.
So Sequential means that data is written in order and read in order. 1,2,3,4,5,6 etc.
Random would be if data was fragmented all over the card so it would read or write 1,6,3,5,4 etc. This slows things down a lot.
I think some of the results might be testing the sim card, or maybe the internal memory is divided up.
Alik: Bravo for being the only place Google could find with relevant information on the S8 and whether it is UHS-II compliant. I’ve been searching for a month, talked with Samsung reps… nobody knows. I posted this blog link in an XDA thread so others can follow your testing. Thank you from many!
Link?
Hello Alik, I posted a comment earlier this morning but it’s no longer there. May I ask if you might be so kind as to see what might have happened? My comment ought not have been controversial, as it’s mostly technical vis-a-vis types of Micro SD cards, etc. Thank you.
Hey WhippetNYC, your previous post included a link so it was awaiting moderation. I wasn’t able to check comments yesterday. I approve every comment that’s not spam.
In answer to your question, the speed tests were done in windows 10. I don’t have the S8 because I’m ordering it from BHphoto as an unlocked version since I don’t plan to keep it and they don’t have any available until early May. I’ve been trying to find anyone else that has the phone but nobody I know has it so I can’t test the cards until they are in stock. It’s very frustrating.
And thanks for the feedback on Samsung cards. There are so many different model numbers that do different things, I’ll try to clarify which card exactly I have based on model number on my next update.
I’m still trying to see if I can get the phone sooner. But let me know if there is anything else you want to see when I do the tests in-phone. Maybe I’ll just walk into Verizon this weekend and get one cash.
Hi Alik, thanks for your reply. May I ask if I should repost that “lost post” or might you moderate/post it after reading it please? Thanks.
I approved it. It went through.
Alik, I just picked up a SanDisk Ultra UHS-I Premium edition 200Gb C10 card for my S8+. How can I tell if it’s the old version (marked Don’t Buy) or the new version. Thank you,
The old version has this serial: SDSDQUAN-064G-G4A Also, the new version is made in China. I think the old version was made in Malaysia, I’m out of town so I can’t confirm for sure.
See on your packaging where the card was made. If it’s made in China I think you’re good to go.
That Delkin 64GB UHS-II… this is how it performs on a Samsung Galaxy S8 (Snapdragon 835 model).
https://uploads.disquscdn.com/images/8bc80d1109b889f4c2d543252e1eebf92bfabaaeeb0720a25f0cf8e63566ee83.png
The Delkin 64GB UHS-II
outputs 62MB/s of read/write performance when installed in a Samsung Galaxy S8 Snapdragon 835 Phone.
https://uploads.disquscdn.com/images/7a5fd5bf55b7e38eb15d8db0d3a5a42694ccf7c4bf693820f94ca32a4f08d05c.png