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16GB Micro SD Class 6 speed issues

I originally had an 8gb class 4 card and when transferring files between my Nexus and PC I noted speeds of up to around 3mb per second.
I recently invested in a 16gb class 6, but now when I transfer files I am very lucky to even reach 1mb per second. This card is incredibly slow, is this right? I thought class 6 were supposed to be at around 6mb's per second?

strange that the speed is less that the class 4 sd, but u cud confirm the card transfer speed using a card reader
but in any case, you shud note that the phone limits the transfer speeds so u mite never get the full transfer speed of a class 6 card...

Oh, I did not know that the phone would limit the speeds, still, it does seem strange that the speed is less than my class 4.
I shall do what you suggested and try and get hold of an adapter to use my card reader

dannstarr said:
I originally had an 8gb class 4 card and when transferring files between my Nexus and PC I noted speeds of up to around 3mb per second.
I recently invested in a 16gb class 6, but now when I transfer files I am very lucky to even reach 1mb per second. This card is incredibly slow, is this right? I thought class 6 were supposed to be at around 6mb's per second?
Click to expand...
Click to collapse
Where did you buy this card from. If it was off ebay, then it could be a fake & that would explain the 1mb transfer speed.

I recently bought a Kingmax 16GB Class6 microSD card. While I was initially transferring my files from my Sandisk 8GB Class2 microSD card, I noticed that the transfer rate was kind of slow, so I decided to do some benchmarking.
Software: CrystalDiskMark 3.0
3 different microSD cards using same USB card reader
Card #1 - Sandisk 8GB C2
Card #2 - Kingston 8GB C4
Card #3 - Kingmax 16GB C6 (new one that I just bought)
Here are the results (Seq Read; Seq Write; Random Read; Random Write):
Card #1: 17.08MB/s; 5.13MB/s; 17.09MB/s; 1.05MB/s
Card #2: 17.23MB/s; 9.53MB/s; 17.23MB/s; 1.92MB/s
Card #3: 16.05MB/s; 5.22MB/s; 16.73MB/s; 1.02MB/s
Summary: My new Class6 card was about the same speed as my Class2 card.
I approached the vendor and they tested a few other Kingmax card that they had in stock... all cards were reportedly about the same speed as the one they sent me. They swear that it's not fake. Maybe its a bad batch of cards but somthing is weird/wrong. Anyways... I'm sending my card back for a refund. I am going to stick to my Kingston Class4 card now.

1MB/sec can be indicative of USB 1 speeds, is OP sure that its connecting @ USB 2?
The class is supposed to be the minimum write speed, and I assume that to be sequential.

>Kingston
isn't that ring the bell? I mean they are pretty expensive....
I think if you go beyond certain level of quility, the pay off of such c/p ratio will get narrowed and you can't tell difference......
either go dirt cheap or go super HD expensive, middle is kind of "uh they are more expensive than dirt cheap but not even close to those expensive things....."
like my AMD vs INTEL war, cheapest AMD almost always beat middle/low Intel by cost + performance, or just go get best INTEL and enjoy the hell out of it.
happy new year

bought Kingston sdhc class 4 BUT....

Hi
I bought a Kingston 8GB SDHC Class 4 card today, I used a Class 2 before, anyway, I copied a lot of music (about 4GB) to the card from the computer but I don't even get close to 4MB/s only 1.38MB/s, have I done something wrong or is it a problem with the card?
thanks

If you're copying file to your phone over usb it will be capped at 2MB/s. It's the phone's fault, not your card. I bought a 16gb class 6 without knowing this and now I have to take my memory card out if I want to take advantage of the write speeds.

Gille1 said:
Hi
I bought a Kingston 8GB SDHC Class 4 card today, I used a Class 2 before, anyway, I copied a lot of music (about 4GB) to the card from the computer but I don't even get close to 4MB/s only 1.38MB/s, have I done something wrong or is it a problem with the card?
thanks
Click to expand...
Click to collapse
You may have been scammed. To know for sure, you should run the h2testw program against the new card. It's quite common for scammers to pass off 2GB cards as 8, 16, or even 32GBs. They can program the card to tell your PC that they are bigger than they actually are.
The h2testw script can test this by writing 8 1GB files (approximately) to your card.
Good luck!

16gb micro sdhc class 10, write speed 6mb/s?

Hello!
I bought Kingston 16gb class 10 micro sdhc card and I tested it on my nexus one getting result 6mb/s and in unbutu getting same results. Both was directly pluged (Not Usb). I closed every running application in nexus one and I got same result. I also tested in different partitions and in ext2 I was getting little slower result than in fat32. But both were same or under 6mb.
Is there something wrong with the card or is it issue with nexus one that android 2.2 doesnt support class 10?

elkyur said:
Hello!
I bought Kingston 16gb class 10 micro sdhc card and I tested it on my nexus one getting result 6mb/s and in unbutu getting same results. Both was directly pluged (Not Usb). I closed every running application in nexus one and I got same result. I also tested in different partitions and in ext2 I was getting little slower result than in fat32. But both were same or under 6mb.
Is there something wrong with the card or is it issue with nexus one that android 2.2 doesnt support class 10?
Click to expand...
Click to collapse
please include where it was purchased, how much, and if there are any serial numbers/stamps on the card. there are known fakes in circulation (even brick and mortor retailers) fyi.

http://www.verkkokauppa.com/popups/prodinfo.php?id=1244 , bought for 101 euros. Serial in the card: SDC10/16GB N0206-001.AD00lF Taiwan.
ANd on adapter reads CHINA

wow thats really slow i have a 16Gb class 4 and i get 7 ~ 8 mb write speeds when the card is in N1 and connected with usb.

I would assume it's the card because as I and someone else stated above, get higher speeds with a lower class card.
As stated here:
It's my understanding that the "Class" simply refers to speed rating and thus should not effect compatibility. As long as the card supports the microSDHC standard and isn't any larger than 32gb it should work. You should also note however that in the past, vendors have claimed a higher class rating when the card did not actual perform that fast. I suggest buying from a trusted vendor with a good name.

32GB SD Card
Anyone tested the 32GB card, I know it's only class 2....

Android Class 10, SDHC3.0 compliant ?
elkyur said:
Hello!
I bought Kingston 16gb class 10 micro sdhc card and I tested it on my nexus one getting result 6mb/s and in unbutu getting same results. Both was directly pluged (Not Usb). I closed every running application in nexus one and I got same result. I also tested in different partitions and in ext2 I was getting little slower result than in fat32. But both were same or under 6mb.
Is there something wrong with the card or is it issue with nexus one that android 2.2 doesnt support class 10?
Click to expand...
Click to collapse
Class 10 should be supported, but they are usually SDHC3.0 card which is new I think...
I have a kingston class 10 as well, same issue, read speed is good but write speed is rated as 2gb, I tried to change the sector size to 4k and still the same.
For those thinking it's a fake card it is not! when I place the card in an adaptor I do 10MB write and close to 16MB read so this is a class 10.
I am not sure if it's the SDC tester app that is wrong or the phone
but since the phone behave fairly well compared to my class 4 card it could be the application. I will do some internal transfer tomorrow to see how fast they go

me too
P00r said:
Class 10 should be supported, but they are usually SDHC3.0 card which is new I think...
I have a kingston class 10 as well, same issue, read speed is good but write speed is rated as 2gb
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Click to collapse
Same card on my HTC Desire... same results... only 2mb/s write beside 15Mb/s read

gary.lavin said:
Anyone tested the 32GB card, I know it's only class 2....
Click to expand...
Click to collapse
See my comparison of Sandisk 16Gb vs Kingstonm 32Gb Class 4 card :-(
http://forum.xda-developers.com/showthread.php?t=830087
I just saw your thread in this forum after I posted mine in the other
Sorry
G.

SD card upgrade

Hey guys just need a little help here im looking to buy a Dane elec either 8 or 16 gig sd card for my atrix 2 after trading in my itouch 4gen 32 gig at GameStop and getting the new nexus 7 tablet and will have about $25 left over to buy a SD card from them, will either of these SD cards cause problems with my ATRIX 2?
Sent from my MB865 using xda premium

atrix2noob said:
Hey guys just need a little help here im looking to buy a Dane elec either 8 or 16 gig sd card for my atrix 2 after trading in my itouch 4gen 32 gig at GameStop and getting the new nexus 7 tablet and will have about $25 left over to buy a SD card from them, will either of these SD cards cause problems with my ATRIX 2?
Sent from my MB865 using xda premium
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Click to collapse
Not as long as it is a class 6 or lower SDcard. If it is a class 6 or a class 4 you will be golden.

It doesn't list a class number would you know what number they usually are?
Sent from my MB865 using xda premium

atrix2noob said:
It doesn't list a class number would you know what number they usually are?
Sent from my MB865 using xda premium
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Click to collapse
Nope, because they can be from a class 2 to a class 10, and they come in all sizes and classes.... the higher the class the faster the SDcard.
You might have to do some research on the vendors website, to find out what class that card is. Again just make sure it is a class 6 or lower.

atrix2noob said:
It doesn't list a class number would you know what number they usually are?
Sent from my MB865 using xda premium
Click to expand...
Click to collapse
Rule of thumb is if it doesn't say then its class 2.anything higher and it should have a circle on the card with a 4, 6, 10 etc in it.
Motorola lied and I'm still locked mb865

mtnlion said:
Rule of thumb is if it doesn't say then its class 2.anything higher and it should have a circle on the card with a 4, 6, 10 etc in it.
Motorola lied and I'm still locked mb865
Click to expand...
Click to collapse
I have a 16GB class 4 that does not list the class on the card itself, but on the package and on the sandisk website it lists the model that I have as a class 4.

Just putting this info out there for anyone. I bought a 32gb class 4 SanDisk and it works flawlessly with this phone. I was skeptical at first because of the size but I've been using it for two weeks now without any problems.
Sent from my MB865 using xda premium

Just for the record, the class rating is the write speed which is more relevant because you'll want to add content to the card; reads speeds on SD cards are typically - and I say "typically" because in testing over 200 different sizes and brands one time (took a full day to do it) the typical read speed was about the same across them all on average - about 17.5MB/s (that's Megabytes per second read speed).
The write speed is what drags things down when it comes to adding content to SD cards, so... the higher the write speed, the faster the card should be able to store the content you're feeding it.
Class speed = approximate sustained write speed so...
Class 2 = 2MB/s on average sustained
Class 4 = 4MB/s
Class 6, etc up to Class 10 at 10MB/s.
Now, sustained means you have a big file like a movie file, perhaps a few hundred megabytes in size - transferring that one big file is the most efficient use of the card's write ability and will usually give you the actual class/write speed.
It's when you're transferring a lot of smaller random files that you'll notice you're taking a speed hit. Case in point:
You have a 100MB file and you transfer it to a Class 4 SD card, it'll most likely take between 25 (best possible throughput to 35 seconds on average (4 to 4.5MB/s max sustained write throughput).
Contrast that with say 12 mp3 files that total about 100MB, each file slightly different from maybe 5.5 to 10.5MB in size. Now, doing that transfer will take far longer than even the 35 seconds on the same exact Class 4 card because it requires more time to do the random writes when each file "breaks" the throughput going to the card. You're probably looking at 45 seconds or more for roughly the same amount of data but broken into smaller "random" chunks, and the speed hit gets even worse as the size of the files you're copying decreases.
If you start transferring a ton of image files like JPEGs to an SD card, about 100MB of them, oh boy... go make a cup of coffee or have lunch or something.
That's what Class speed means - it's only relevant to the sustained write speed on the card, aka how fast you can put content on it.
Hope this helps...

jimbridgman said:
I have a 16GB class 4 that does not list the class on the card itself, but on the package and on the sandisk website it lists the model that I have as a class 4.
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Click to collapse
Really? Never saw an unmarked one that wasnt a 2. I stand corrected.
Motorola lied and I'm still locked mb865

Fyi i'm running a Patriot class 10 card in my a2 with no problems

chriselmore said:
Fyi i'm running a Patriot class 10 card in my a2 with no problems
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Click to collapse
You WILL have issues so be prepared, and by all means do NOT run apps off SDcard or you WILL have issues and lose data!

Also anyone find out how to move apps on the SD to the internal space?
Sent from my MB865 using xda premium

chriselmore said:
Fyi i'm running a Patriot class 10 card in my a2 with no problems
Click to expand...
Click to collapse
Ditto. No issues yet.

In addition to not moving applications to the SDHC it might be a good idea to follow Patriot's advice regarding formatting. The suggestion was posted by Patriot in response to a review of a 32GB class 10 microSDHC.
Patriot acknowledged a problem with hemorrhoid OS and 32GB class 10 cards and suggested a temporary fix of performing a full format on a Windows PC with a 32kb allocation size, obviously FAT32 since stock hemorrhoid does not recognize NFTS.
The reply can be found in this review although the specific page will change if more reviews are added.

Thanks! I guess hemorrhoid OS is a real pain in the a** to work with.
Thanks! Its been a bad month so far. I really needed that laugh.
Motorola lied and I'm still locked mb865

Atrix 2 has been facing trouble when used a sd card of above class 6. I've a 32 gb class 10 card but i faced many problem when i used it last month then i had to replace it with 16gb class6 of kingston.
Sent from my MB865 using xda app-developers app

random or sequential ??
br0adband said:
Just for the record, the class rating is the write speed which is more relevant because you'll want to add content to the card; reads speeds on SD cards are typically - and I say "typically" because in testing over 200 different sizes and brands one time (took a full day to do it) the typical read speed was about the same across them all on average - about 17.5MB/s (that's Megabytes per second read speed).
The write speed is what drags things down when it comes to adding content to SD cards, so... the higher the write speed, the faster the card should be able to store the content you're feeding it.
Class speed = approximate sustained write speed so...
Class 2 = 2MB/s on average sustained
Class 4 = 4MB/s
Class 6, etc up to Class 10 at 10MB/s.
etc etc etc .
Click to expand...
Click to collapse
Have googled a lot on this and stuck on one thing now....
Class 2 cards are poor in sequential write but they are good in random writes while Class 10 cards are good in sequential writes but poor in random writes. The lower the class the better is the random write and poor is the sequential write; vice versa.
So what is more important to have an optimum speed on cell, random writes or sequential ??
I guess random it is. cause sequential writes are more often in large file writing.
Can someone put some light on this ? for applications and other little writing tasks class 2 will be good whereas for copying data from or to PC or shooting full HD videos I guess class10 would be good !!
However m not sure about Android memory usage. What is more important from OS point of view, Random or Sequential write ?

lparihar9 said:
Have googled a lot on this and stuck on one thing now....
Class 2 cards are poor in sequential write but they are good in random writes while Class 10 cards are good in sequential writes but poor in random writes. The lower the class the better is the random write and poor is the sequential write; vice versa.
So what is more important to have an optimum speed on cell, random writes or sequential ??
I guess random it is. cause sequential writes are more often in large file writing.
Can someone put some light on this ? for applications and other little writing tasks class 2 will be good whereas for copying data from or to PC or shooting full HD videos I guess class10 would be good !!
However m not sure about Android memory usage. What is more important from OS point of view, Random or Sequential write ?
Click to expand...
Click to collapse
You CANNOT run a class 10 card well in this phone. I recommend getting a class 6 card, or a class 4 card, and be done with it. Those are 100% known to work with the atrix 2 without issues. Don't worry too much about which is better for what, with this phone the class 4 and class 6 seem to work the best, and give decent performance. And yes it will take a long time to copy 16GB of music and movies to your SDcard from a computer as the writes for a class 4 or 6 are mediocre for that, but decnet when used for anything on the phone itself. Just be very careful about running apps on the SDcard with this phone, it can be touchy and lose the apps and data on reboot, even though it is still on the SDcard the phone will not know how to use them and the pointers to the android system may just be gone. Sometimes just reinstalling the app from he play store works and other times you have to format the card... that is the biggest issue with this phone, period.

Atrix 2 can only withstand Class 4.

Darell3 said:
Atrix 2 can only withstand Class 4.
Click to expand...
Click to collapse
That is not true. I have a class 6 32GB card that works perfect, and so do several others that own the atrix2.

Apps on SD card in "merged storage" lag

Hi,
I have my SD card (class 6) merged with my internal storage. Every app I move to the SD card lags like hell! They work perfect when on the internal storage. My storage is starting to fill though as it's only an 8GB device. Any ideas? I've been thinking that if I get a class 3 uhc SD card (they reckon they're up to 60 MB/s) but I'm not sure is that the problem?
Thanks for your advice.

Class 10 should be bare minimum. I am pretty sure the class 6 card is the cause. Uhs 3 is recommended.
Broadcasted from Zeta Reticuli

I would concur with @Gravemind2015 your card is too slow... Although I think a minimum UHS1 card is required to make it usable due to the higher write speed than a Class 10, but I do agree a UHS3 is recommended.
A Class 6 card is just too slow for use as adopted storage, I would convert it back to portable until you can get a new card or it will constantly lag on you.

Thank you for your help
I've bought a UHS Class 3 card, installed it and it's solved the problem.

acejavelin said:
I would concur with @Gravemind2015 your card is too slow... Although I think a minimum UHS1 card is required to make it usable due to the higher write speed than a Class 10, but I do agree a UHS3 is recommended.
A Class 6 card is just too slow for use as adopted storage, I would convert it back to portable until you can get a new card or it will constantly lag on you.
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Click to collapse
sir can i ask? i got same problem here, now i used sandisk micro SDHC UHS-I Class 10 16GB speed up to 48mb/s. but i still got lag, that laggy was from my phone or my sd card? if it cause by sd card, and than i'll buy UHS-3 class 10 speed up to 90mb/s. it will solved my laggy? i used Moto g4 plus 2/16 run with MM 6.0.1

jincuriki said:
sir can i ask? i got same problem here, now i used sandisk micro SDHC UHS-I Class 10 16GB speed up to 48mb/s. but i still got lag, that laggy was from my phone or my sd card? if it cause by sd card, and than i'll buy UHS-3 class 10 speed up to 90mb/s. it will solved my laggy? i used Moto g4 plus 2/16 run with MM 6.0.1
Click to expand...
Click to collapse
The card reader in the 3rd and 4th generation G devices is UHS-1, it's write speed is limited in real world use is limited to about 45mbps, or about 1/2 to 1/3 of the embedded storage chip... You will always have some lag by comparison. Will a U3 card be better? I can't answer that definitively since it would vary based on your specific usage.