Suggestions for microSD

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flarbear

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Feb 24, 2016 at 3:42 AM
[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
Mixza
Samsung
SanDisk
Strontium
 
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Pilz

Pilz

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Feb 24, 2016 at 4:41 PM
Samsung has some new fast micro SD cards under their EVO Pro+ line, and I know Sandisk just released some new ones too. I have a 200GB Sandisk for ym Surface Pro 4 and some other Sandisk Exteme Pro cards laying around.

Here are the links:

64gb EVO Pro+ (95mb/s read 90mb/s write)
http://www.amazon.com/gp/aw/d/B012DTJ8NU/ref=psd_mlt_nbc_B01273L37G_rbi


64gb Sandisk Exteme Pro (95mb/s read 90mb/s write)
http://www.amazon.com/gp/aw/d/B00O47H8LY/ref=mp_s_a_1_11?qid=1456331926&sr=8-11&pi=AC_SX236_SY340_FMwebp_QL65&keywords=sandisk+micro+sd

---------- Post added at 05:41 PM ---------- Previous post was at 05:38 PM ----------

That card is slow in terms of read/write speeds so he's better off with a 64gb card that's faster
 
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flarbear

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Feb 24, 2016 at 7:48 PM
Yes, according to the specs and claims Evo+ (80/20) is good for HD video recording, but Pro+ (95/90) is good for 4K video recording.

The tests seem to back up the speed ratings:

https://www.ephotozine.com/article/samsung-pro--evo--microsd-memory-card-review-28061

It looks like you can get Evo+ for half the price (or similar price for twice the storage) compared to the Pro+, but the Pro+ isn't too bad, price-wise.

The new Sandisk UHS-II cards are much more expensive and they have a new pin out (backwards compatible) that it isn't clear if the S7 supports. They also have amazing read speeds (275 vs 95), but the write speeds are not that much better than the UHS-I/U3 cards (100 vs 90). I'm wondering if this would help with things like scrolling through gigabytes of saved camera photos?

Does the S7 even support the UHS-II bus speeds/pins?
 
vivelafrance

vivelafrance

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Feb 24, 2016 at 8:27 PM
I wouldn't choose the Evo ones from Sandisk. These are nowhere as fast as the "Extreme Pro", or "Samsung Pro+" ones.
I'm angry at Sandisk cause they will only release their newly superfast microSD cards way after the release of the Galaxy S7 and I need one NOW, not 6 months after I receive my phone... Pretty stupid from them, they should have planned this better.

Right now, i'm still hesitating between these 2:

SanDisk Extreme PRO 64GB microSDXC UHS-I/U3 Memory Card 95MB/s Read FFP (SDSDQXP-064G-​FFPA)
SanDisk Ultra 200 GB microSDXC Memory Card up to 90 MB/s, Class 10


I actually wanted the Extreme Pro mentioned above but in its 128GB version. However it's not out yet... very disappointed
 
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flarbear

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Feb 24, 2016 at 8:36 PM
I haven't been able to find any specs or tests of the write speed of the Lexar card. There are a couple of anecdotal reports of write speeds in the 40MB/s range in the Amazon comments, but at least one of those was revised when they changed their test environment to 60MB/s.

On Lexar's site they list both this "Professional 1000x" range that has 150MB/s read speed and a newer "Professional 1800x" range that has 270MB/s speeds similar to the latest Sandisk cards, but they simply say "write speeds lower" without any spec or claim...
 
vivelafrance

vivelafrance

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Feb 24, 2016 at 8:38 PM
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flarbear

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Feb 24, 2016 at 8:45 PM
vivelafrance said:
I wouldn't choose the Evo ones from Sandisk. These are nowhere as fast as the "Extreme Pro", or "Samsung Pro+" ones.
I'm angry at Sandisk cause they will only release their newly superfast microSD cards way after the release of the Galaxy S7 and I need one NOW, not 6 months after I receive my phone... Pretty stupid from them, they should have planned this better.

Right now, i'm still hesitating between these 2:

SanDisk Extreme PRO 64GB microSDXC UHS-I/U3 Memory Card 95MB/s Read FFP (SDSDQXP-064G-​FFPA)
SanDisk Ultra 200 GB microSDXC Memory Card up to 90 MB/s, Class 10


I actually wanted the Extreme Pro mentioned above but in its 128GB version. However it's not out yet... very disappointed
Click to expand...


The Ultra 200 is not shown to be U1 or U3 and has no spec on write performance (only read performance) even on the SanDisk web site. Given that they list write performance for most of their other cards, I take this to mean that they aren't making any minimum write guarantees beyond the Class10 logo on the card which only guarantees 10MB/s...
 
vivelafrance

vivelafrance

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Feb 24, 2016 at 8:49 PM
flarbear said:
The Ultra 200 is not shown to be U1 or U3 and has no spec on write performance (only read performance) even on the SanDisk web site. Given that they list write performance for most of their other cards, I take this to mean that they aren't making any minimum write guarantees beyond the Class10 logo on the card which only guarantees 10MB/s...
Click to expand...
I had the same thought but when I read reviews, comments, I noticed that no one complained, including the ones making 4K videos... so I don't know...
 
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flarbear

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Feb 24, 2016 at 9:03 PM
vivelafrance said:
I had the same thought but when I read reviews, comments, I noticed that no one complained, including the ones making 4K videos... so I don't know...
Click to expand...
I was looking at these charts on Panasonic's web site and they claim that U3 is required for 4K (apparently U1 == Class10, U3 == 3xClass10?):

http://panasonic.net/avc/sdcard/features/speed_class.html

On the other hand, in the chart near the top, the speed bar for the U1/Class10 speed class extends above HD Video into the 4K range, but it doesn't cover the 4K range. Does that mean if you are using a highly compressed 4K stream then it can keep up?

Also, if you look lower, the main issue is minimum guaranteed write speed. They show a Class 4 card keeping up with HD video for a while and then dropping frames at some point and failing a ways into the operation. Speed class is a minimum write speed guarantee so if the videos are short then caching and other considerations may mean that the problem doesn't show up right away, but if you try a sustained capture then you may be out of luck. With 4G RAM the S7 might be able to buffer quite a bit of 4K video in RAM and deal with slower cards, but a smaller camera might rely more on the raw write speed of the card itself.
 
vivelafrance

vivelafrance

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Feb 24, 2016 at 10:55 PM
flarbear said:
I was looking at these charts on Panasonic's web site and they claim that U3 is required for 4K (apparently U1 == Class10, U3 == 3xClass10?):

http://panasonic.net/avc/sdcard/features/speed_class.html

On the other hand, in the chart near the top, the speed bar for the U1/Class10 speed class extends above HD Video into the 4K range, but it doesn't cover the 4K range. Does that mean if you are using a highly compressed 4K stream then it can keep up?

Also, if you look lower, the main issue is minimum guaranteed write speed. They show a Class 4 card keeping up with HD video for a while and then dropping frames at some point and failing a ways into the operation. Speed class is a minimum write speed guarantee so if the videos are short then caching and other considerations may mean that the problem doesn't show up right away, but if you try a sustained capture then you may be out of luck. With 4G RAM the S7 might be able to buffer quite a bit of 4K video in RAM and deal with slower cards, but a smaller camera might rely more on the raw write speed of the card itself.
Click to expand...
I'm not entirely sure the RAM is an important factor here. Are you sure it is? First it depends how much RAM Android 6 and third-party apps take and then how long the RAM has to keep the video into memory before the card can write them onto itself...
I really wish the brand new 200MB/sec cards that will be out Q2 2016 were out now!
 
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flarbear

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Feb 24, 2016 at 11:02 PM
vivelafrance said:
I'm not entirely sure the RAM is an important factor here. Are you sure it is? First it depends how much RAM Android 6 and third-party apps take and then how long the RAM has to keep the video into memory before the card can write them onto itself...
I really wish the brand new 200MB/sec cards that will be out Q2 2016 were out now!
Click to expand...
I don't know which is why I phrased that as speculation ("might/may"). RAM helps by smoothing over brief periods where the card doesn't keep up with the streaming speed. With no caching at all the card has to write every video frame as it is generated and before the next frame comes along. With RAM, it can stutter on one frame, but be able to catch up on the next. With enough RAM as a buffer/cache the card only has to deliver the required bitrate as an average write speed, not as a guaranteed minimum write speed.
 
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flarbear

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Feb 24, 2016 at 11:56 PM
UnixSlayer said:
UHS-3 are the fastest....
Click to expand...
There is no UHS-3 (yet), only UHS-I and UHS-II. Some Amazon listings say UHS-3 when they mean U3 (though that is short for "UHS Speed Class 3" so it is understandable why they might state it that way, but the accepted way of stating the speed class is "U3" since the "UHS" acronym is already being used to specify the high speed bus support).

SD, SDHC and SDXC are formats. They specify file systems and maximum capacity and card info structures. For instance, SDXC means the card will be formatted with the exFAT file system which may not be supported by all devices unless they specifically mention SDXC support.

UHS-I and UHS-II are ultra high speed buses that can be supported by SDHC and SDXC cards and have faster maximum theoretical transfer rates through the interface, but don't specify anything about the speed of the flash storage itself. UHS-I uses the same pins as regular cards, but UHS-II requires the device to support additional pins in order to get the faster rates.

Class2,4,6,10 and U1 and U3 are speed ratings which guarantee a minimum supported write speed so you know that they can suffice for your application. (Note that they don't say anything about read speed since that is generally not a gating factor and is usually much faster than the write speed anyway.)

Currently U3 is the fastest minimum guarantee, but cards can still vary a lot in speed as long as they meet that minimum. One U3 rated card may barely meet the minimum, while another is 3 times faster. Also, one U3 rated card may reliably write things all day at just over the required speed rating, never dipping below that. Another may write things usually 3x faster, but occasionally have dips that dip down to slower speeds as long as they stay above the minimum guarantee. The latter card will be faster for many things if you are waiting for it to write stuff, but both have the same speed rating because the speed rating represents the minimum speed that it promises for sustained writing. Benchmarks and real world experience can tell you more beyond the speed rating.

https://en.wikipedia.org/wiki/Secure_Digital#Ultra_High_Speed_.28UHS.29_bus
 
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flarbear

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Feb 25, 2016 at 12:05 AM
vivelafrance said:
You mean UHS-I class 3 (or U3) ... lol
UHS-3 doesn't exist yet. "UHS-2 U3" cards will be out later this year (250-280MB/sec).
Click to expand...
Actually UHS-II U3 cards are already out. The 250MB/s read ratings of the newer cards that will be coming out soon are not expressed by either of those numbers.

UHS-II has 2 higher bus speeds - 156MB/s for half duplex operation or 312MB/s for full duplex operation. So these newer UHS-II cards are really the first full duplex cards coming out, but they are still just UHS-II.

[Update: Oops, the following is incorrect:]

The Wikipedia page implies that the extra pins in UHS-II are only needed for full duplex operation which makes sense, but is non-authoritative.

[Correction: Here is what it really says:]

The Wikipedia page mentions that the faster rate of 312MB/s is only available in half duplex mode which is a uni-directional transfer of data either onto, or from the card, but not in both directions at once. The lower 156MB/s speed is in full duplex mode which is a bi-directional mode where you can both transfer data onto and off of the card at the same time. So, basically, they can borrow the write lines to double the read speed or vice versa, but if you want to read and write simultaneously then you are stuck with half the speed. It's not clear how this will be used in practice, hopefully the devices and cards will dynamically choose whether to work in full or half duplex mode depending on the operations being performed at any point in time.

[End of correction update]
 
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flarbear

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Feb 25, 2016 at 8:12 PM
I went down to the local Best Buy last night since they have the Sandisk Extreme Plus 64gb card on sale now ($49 down from ?$149?, but I assume that list price is never actually used in practice).

While I was there I found a 64gb Samsung Pro+ with a shelf tag of $49 as well so I bought both. It turns out the shelf tag on the Pro+ was wrong and it rang up as $89, but I got them to match their own shelf tag and got both for $49.

I just ran some benchmarks using the SD card reader on my SurfaceBook and got the following results.

The Sandisk has faster reads, especially the random reads, but the Samsung has faster writes. Both are plenty fast enough to keep up with a 4k video stream, though (which requires 30MB/s speed class), so the faster reads of the Sandisk may make it a better choice. The difference in writes is much larger than the difference in reads, though, so if you write a lot then that may make a difference, but most people tend to read much more than they write and so as long as the card can keep up with the 4k video streaming rate, the read speeds can be more compelling.

One thing to note is that I tested the Samsung twice on my desktop rig until I decided that the card reader I have on it is only a USB2 reader and that was limiting my results (40MB/s-ish for two test runs) and then I switched to the SurfaceBook where I ran the two results posted here.

I tried to run the AS SSD benchmark, but not only did it insist on running the same amount of data for both the random and sequential tests, making the sequential tests take over 20 minutes apiece to run, but it also exhibited flaky behavior on the queue depth tests that I've seen before that the Crystal benchmark doesn't seem to be affected by. In the past, this flaky behavior can be fixed by updating some drivers, but I didn't want to bother since experience has shown that its results are not that different from the Crystal results once you get done poking everything you need to poke to make the AS benchmark happy...

Samsung Pro+ in Samsung's card reader in SurfaceBook SD slot
View attachment 3660028

Sandisk Extreme Plus in Sandisk's card reader in SurfaceBook SD slot
View attachment 3660029

Here's an update with the results of the A1 SD Benchmark app in the phone itself. The internal storage gets 279/99 speeds but the Samsung Pro+ drops from 92/83(seq.) on the desktop to 61/40 in the phone itself.

Samsung Pro+ in Galaxy S7 Edge slot
Screenshot_20160301-041723.jpg
 
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