[Samsung Galaxy S7 Edge Accessories] flarbear:
[TLDR/Summary] Many have pointed out that unless you are constantly loading new content onto the card, the only thing that matters is whether it can keep up with video recording. With sample 4k videos on the S7 Edge only coming in around 6MB/s byterate, any U1 or U3 card should be fine. If you read large files from it then the read speeds matter, but most any card rated for 60MB/s or higher benchmarks around 60MB/s in the S7 Edge's card slot - even cards that are theoretically capable of up to 270MB/s read speed in a desktop reader. Just about any of the cards discussed below (see a summary at the end of this post) should suffice, so feel free to choose based on total storage, price, and factor in write speeds only if you are in the group that copies data to the card a lot.

To be clear - you should be fine with a UHS-I card rated U1 or U3 with a claimed read speed at least 60MB/s. A U3 card will help when you load new data onto it (vs a U1 card).

A "Class 10" card has the same guaranteed minimum write speed as a U1 card, which means it should be high enough for 4k video on the S7, but they often benchmark slower on reads than U1 cards - not so slow that they would fail at 4k video, but less write speed on average.

[And now for the long story...]

After participating in the thread a while and reading up on things, my Mobile Ultra cards are only UHS-I. Class U1 cards are most likely fine in practice given the low bitrate of the S7 4k video codec, but since they aren't guaranteed for 4K video and I never pass up an opportunity for new gadgets, it looks like I'll be in the market for a new card hopefully before my S7 Edge arrives (update - it arrived shortly after I started this thread)...

Some terms (with data taken from the sdcard.org web site)...

Card format:

SD: up to 2GB storage (uses FAT file system)

SDHC: up to 32GB storage (uses FAT file system)

SDXC: up to 2TB storage (uses exFAT file system)

Bus speeds (speed of data through the pins on the card):

Normal speed bus - 12.5MB/s

High speed bus - 25MB/s

UHS-I bus (only on SDHC,SDXC): 50 or 104MB/s depending on implementation

UHS-II bus (only on SDHC,SDXC): 156 or 312MB/s depending on full/half duplex

(UHS-II defines new pins on the card to achieve these higher speeds, 312 MB/s is uni-directional only, 156MB/s is bi-directional)

Speed class (minimum guaranteed sustained write speed)

(Note: maximum burst write speed and read speeds are likely much higher, but speed class is a guaranteed minimum for writing/recording)

Class 2 - 2MB/s

Class 4 - 4MB/s

Class 6 - 6MB/s

Class 10 - 10MB/s

U1 (requires a UHS bus) - 10MB/s (equivalent to Class 10, but max speeds may be higher than a non-UHS card)

U3 (requires a UHS bus) - 30MB/s (listed as required for 4k video recording, but U1 might work for some 4k codecs with lower bit rates)

So, an SDHC, UHS-I, U3 card uses FAT file system with a maximum size of 32GB and an ultra high speed bus (between 50MB/s and 104MB/s) and a guaranteed sustained write speed that exceeds 30MB/s at all times and under all conditions.

As another example, the newly announced cards that claim 250+MB/s read speeds must be using the UHS-II half-duplex mode which means they can only read that fast when they use all data lines for output which requires them to turn off writing at the same time. The sophistication of when to turn from reading to writing (or from full duplex to half duplex) remains to be seen...

Data collected from various contributors to this thread:

(If you run a benchmark, please make a run on both A1 SD and Androbench and post screen shots of the results if you can.)

(For Androbench, please make sure you go into the settings and select the external card first as it benchmarks the internal memory by default...)

Here is a Google Spreadsheet with results and a graph: https://docs.google.com/spreadsheets/d/1ay8Ibez8OntSfLZRpqqaCOGRGvh7HxOY_Um9JYBz5_s/edit?usp=sharing

(Graphs are on sheet1, A1 SD results are on sheet3, Androbench results are on sheet3)

Here is the direct link to the chart of A1 SD sequential benchmark results: https://docs.google.com/spreadsheet...m9JYBz5_s/pubchart?oid=882229439&format=image

Here is the direct link to the chart of Androbench results: https://docs.google.com/spreadsheet...m9JYBz5_s/pubchart?oid=100964648&format=image

Some pointers to benchmarks of cards inside the S7 Edge (alphabetized by Manufacturer, then model name, then by numeric size, then by benchmark and then by order of posting):

Lexar

128GB Lexar 1000x (UHS-II, U3)

(One report of the card crashing a phone: http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65970551)

(A few more reports of issues with the card not responding until the phone is restarted: http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66288991)

A1 SD 65.97 / 40.36 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65794089)

A1 SD 65.13 / 39.50 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65891080)

64GB Lexar 1800x (UHS-II, U3)

A1 SD 68.16 / 56.20 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66196944)

Androbench sequential 74.33 / 51.59 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66196944)

Androbench random 9.4 / 1.07 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66196944)

128GB Lexar 1800x (UHS-II, U3)

A1 SD 64.40 / 47.93 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65804432)

A1 SD 70.01 / 50.02 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66041783)

Androbench sequential 73.70 / 19.06 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66033961)

Androbench random 9.27 / 0.53 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66033961)

Unspecified 62.26 / 50.81 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65743896)

Mixza

128gb Tohaoll (UHS-I, U1)

A1 SD 63.27 / 21.43 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66365849)

Androbench sequential 73.69 / 20.36 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66365849)

Androbench random 2.83 / 1.13 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66365849)

Samsung

64gb Samsung Evo+ (UHS-I, U1)

A1 SD 64.66 / 22.30 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65807311)

A1 SD 65.95 / 22.20 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65807311)

64gb Samsung Pro (not Pro+) (UHS-I, U3)

A1 SD 68.33 / 34.69 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66021206)

64gb Samsung Pro+ (UHS-I, U3)

A1 SD 60.99 / 39.77 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65598723)

A1 SD 67.80 / 36.09 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65744757)

A1 SD 67.12 / 55.41 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66207913)

Androbench sequential 79.51 / 65.59 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65610108)

Androbench sequential 73.67 / 65.84 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65744757)

Androbench sequential 74.21 / 61.42 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66207913)

Androbench sequential 72.97 / 62.03 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66865127)

Androbench random 13.94 / 3.47 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65610108)

Androbench random 12.27 / 2.14 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65744757)

Androbench random 7.84 / 1.73 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66207913)

Androbench random 12.14 / 1.56 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66865127)

128gb Samsung Pro+ (UHS-I, U3)

A1 SD 52.41 / 40.90 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65937125)

A1 SD 47.49 / 24.44 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65938993)

A1 SD 55.06 / 48.55 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65973419)

A1 SD 60.05 / 42.19 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66556117)

A1 SD 52.43 / 39.91 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66616524)

A1 SD 60.76 / 42.41 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66677814)

A1 SD 62.44 / 34.87 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66735488)

Androbench sequential 75.85 / 63.94 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65937125)

Androbench sequential 73.48 / 61.78 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65946187)

Androbench sequential 75.61 / 62.74 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65973419)

Androbench sequential 70,81 / 57.65 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66556117)

Androbench sequential 74.76 / 63.18 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66616524)

Androbench sequential 71.27 / 62.59 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66735488)

Androbench random 13.2 / 1.67 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65937125)

Androbench random 12.57 / 1.6 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65946187)

Androbench random 13.12 / 1.53 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65973419)

Androbench random 11.26 / 1.7 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66556117)

Androbench random 12.23 / 2.16 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66616524)

Androbench random 11.29 / 1.62 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66735488)

SanDisk

16GB SanDisk Extreme (UHS-I, U3)

(The next 3 data points are 3 separate runs of Androbench on a single card)

Androbench sequential 63.0 / 41.44 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench random 11.19 / 1.16 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench sequential 62.67 / 41.17 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench random 10.99 / 1.32 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench sequential 63.18 / 39.74 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench random 11.1 / 2.69 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

(The next 2 data points are 2 separate unique runs of Androbench on a single card. The posting contains a 3rd run which is a dup of the 2nd run according to the benchmark dates.)

Androbench sequential 62.11 / 42.8 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench random 10.9 / 1.29 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench sequential 61.61 / 42.92 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench random 10.85 / 2.89 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

64GB SanDisk Extreme (UHS-I, U3)

(Note that the sequential write speeds listed below do not meet the minimum requirement of speed class U3, though this is just a single data point so far - same card, 3 benchmarks on it)

A1 SD 58.89 / 21.28 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66590002)

Androbench sequential 76.5 / 21.64 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66590002)

Androbench random 8.53 / 0.29 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66590002)

(On this new test, the card meets the minimum requirements of speed class U3, so perhaps the numbers above are an outlier)

A1 SD 73.59 / 35.48 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67386836)

128GB SanDisk Extreme (UHS-I, U3)

Androbench sequential 83.25 / 50.2 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post68315604)

Androbench random 13.66 / 4.29 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post68315604)

64GB SanDisk Extreme Plus (UHS-I, U3)

A1 SD 70.28 / 32.43 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65792181)

64GB SanDisk Extreme Pro (UHS-I, U3)

A1 SD 72.99 / 61.07 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65728785)

A1 SD 75.36 / 64.96 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65911731)

A1 SD 65.25 / 56.92 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66037195)

A1 SD 76.59 / 57.10 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66735488)

Androbench sequential 77.26 / 43.49 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66011441)

Androbench sequential 78.78 / 63.14 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66032229)

Androbench sequential 81.71 / 44.47 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66037195)

Androbench sequential 78.19 / 62.43 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66735488)

Androbench sequential 75.92 / 65.3 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66864264)

Androbench random 7.95 / 3.15 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66011441)

Androbench random 11.3 / 3.19 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66032229)

Androbench random 12.52 / 2.94 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66037195)

Androbench random 11.0 / 3.15 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66735488)

Androbench random 10.72 / 3.1 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66864264)

64GB SanDisk Mobile Ultra (UHS-I, Class 10)

A1 SD 40.31 / 10.91 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66047660)

Androbench sequential 41.66 / 8.44 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66047660)

Androbench random 5.93 / 0.67 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66047660)

16GB SanDisk Ultra (UHS-I, Class 10)

Androbench sequential 37.89 / 12.37 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

Androbench random 4.61 / 0.58 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post67382140)

128GB SanDisk Ultra (UHS-I, Class 10)

A1 SD 68.87 / 17.56 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65809092)

A1 SD 68.29 / 23.78 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66126918)

Androbench sequential 75.72 / 25.93 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65798166)

Androbench sequential 76.77 / 29.91 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66126918)

Androbench random 8.14 / 2.65 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66126918)

200GB SanDisk Ultra (UHS-I, Class 10)

A1 SD 63.76 / 15.82 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65691124)

Androbench sequential 79.2 / 14.5 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66104584)

Androbench random 5.44 / 0.62 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66104584)

128GB SanDisk Ultra Plus (UHS-I, Class 10)

A1 SD 64.15 / 17.37 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66899362)

Androbench sequential 81.6 / 42.25 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66899362)

Androbench random 9.81 / 2.75 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post66899362)

Strontium

64gb Strontium Nitro (UHS-I, U1)

A1 SD 66.73 / 21.30 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65937494)

Androbench sequential 78.22 / 21.47 MB/s (seq r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65930539)

Androbench random 7.48 / 0.82 MB/s (random r/w) (http://xdaforums.com/s7-edge/accessories/suggestions-microsd-t3321569/post65930539)