# microSD XC painfully slow write-speed



## gunzb

Hi, I've just bought a microSD XC 64GB Samsung Evo from ebay, but there's a problem: 

When I first plugged it in and started writing files on it, it did so at an average speed of 8 mb/s... then when the card had 5gb of data in it, the speed dramatically decreased at roughly 1 mb/s.

So I tried formatting it with SDFormatter, but afterwards it did the exact same thing.

Can someone help me with this? Thanks


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## jamesd1981

What speed class is your msd card ?


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## gunzb

I don't know exactly what that means or how to ascertain it but on the msd, next to SD XC is written "I" and above that 1 in a semicircle


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## jamesd1981

So it is a class 1 UHS card, so it should be fast.

I assume your computer is reasonably powerful ?


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## gunzb

Yes, on USB 3.0 hard disks the transfers reach a 70 MB/s speed (roughly).


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## jamesd1981

It could be the card reader that is restricting the transfer rate, is it a laptop you are using or an external card reader etc


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## gunzb

I've tried two card readers and the laptop's internal reader, and I've always got the same result.


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## jamesd1981

What type of data are you transferring, obviously transferring 1 large file is quicker than transferring multiple smaller files of the same total size.

Try using a free program called, Crystal disk mark to test your transfer speeds accurately

http://crystalmark.info/software/index-e.html


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## gunzb

I'm transferring mp3s mostly (3-10 MBs), but the same happens if I try to transfer bigger files (90-100 MBs).

I downloaded Diskmark, and I ran it but it's been stuck on the "Preparing..." stage for 2 minutes. If it manages to get past it, I'll edit the post.


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## gunzb

It appears to be stuck. (I already closed it and ran it again but nothing happens).

EDIT I also tried the non-shizuku version... nothing.


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## jamesd1981

The preparing heading should stay, but section next to it should change as it progresses to sequential read, sequential write etc.

Try running it on your main drive in case it`s a problem with the card


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## gunzb

Yes, I ran it on my C: drive and it worked as you say. With my microSD it remains at Preparing... stage.


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## jamesd1981

If you are still having trouble with crystal mark, try using diskbench - http://www.nodesoft.com/diskbench

It will use your own files and tell you the transfer rate and time taken.


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## gunzb

This one worked :

Copy File Bench started...

Copy D:\ciao.mp3 to P:\ciao.mp3
  Size: 14592461
  Time: 16255 ms
  Transfer Rate: 0,856 MB/s

Copy File Bench ended


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## jamesd1981

Seems not bad, but kind of hard to tell with 1 small file, try doing larger amount like 1GB

Also if you want to try crystal disk mark again, it could have been the test size was to large for a memory card, try lowering it from default 500MB to the lowest 50MB


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## gunzb

Crystall Mark worked using a 50MB test size even though it seems to be stuck at random write 4KB [1/5], but maybe what I got is enough.

http://postimg.org/image/70zd4s8nd/






EDIT By clicking stop, the program remains in Random Write and cannot be closed. If I close it through the Control Panel, do I risk ruining the msd?


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## jamesd1981

Unusual to see a write speed higher than the read speed.

Try running HD tune free not pro - http://www.hdtune.com/download.html and run the error scan function to check your card, you could also run the benchmark section to confirm your speeds.


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## gunzb

I downloaded it, but on Crystall Mark by clicking stop, the program remains in Random Write and cannot be closed. If I force-close it through the Control Panel, do I risk ruining the msd?


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## jamesd1981

just press, ctrl-alt-del and close crystal mark in the task manager


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## gunzb

That's what I meant, I was afraid of ruining the msd by doing so. But apparently there's no risk so I did it.

These are the results obtained while Crystall was still opened.

http://postimg.org/image/axunnn38d/

http://s23.postimg.org/5r35f9nej/hdt2.jpg


EDIT I managed to close Crystall in the Task Manager, but the process is still going and can't be closed (It says "access denied", maybe because I ran it as Administrator) and the test gives the same results.


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## jamesd1981

Well the card is obviously fine physically, is there an option to turn on indexing on this card ?


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## gunzb

I have no idea how to do that. :/ By the way the speed of files-transfer (my files) is back to 5 MB/s, ever since I did the test on Crystall... (but I don't know it's gonna be permanent)

Is 5 MB/s an appropriate transfer speed for a Class 1 UHF microSD XC card?


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## jamesd1981

If you go to your drives section, locate the msd card and right click, select properties and in the general tab, it may have an option to index the contents of this drive, it is really for faster file searches but may help speed slightly.

The speed does seem a bit slow, I still believe it maybe the card readers that are holding it back, most card readers are basic and slow, perhaps to get faster speeds you may need to invest in a high speed usb 3.0 card reader like these - http://www.bhphotovideo.com/c/buy/Card-Readers/ci/1096/N/4037060555


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## gunzb

Now there seems to be an even bigger problem: 

Yesterday while copying some files to test the effective speed, the entire computer freezed, so I had to force-shut down the laptop by holding the power button for 5 seconds. When I tried to plug it in back after restarting it a message comes up telling me that I have to format the disk to use it.

But when I try to format it, it simply tells me that It's impossible to format.
(And curiously it lists the size of the msd as 1,96 TB[??])


SDFormatter says this: 

"The Memory Card is write-protected. Please release the write protect switch."


Guiformat says this:

"Failed to set volume label
GetLastError()=1005
The volume doesn't contain a recognized file system.
Check that all required drivers for the file system are loaded and the volume isn't damaged."

What can I do?


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## jamesd1981

Does the card have a little lock slider on the side of it ?


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## gunzb

no, it doesn't.


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## jamesd1981

Have you tried formatting in windows instead of SDformatter


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## gunzb

Yes, it merely tells me that it's impossible to format.


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## jamesd1981

Does it show up in your drives list ?


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## gunzb

If you mean in the Computer screen, next to C:\, D:\ yes, but if I try to open it, it tells me that the drive needs to be formatted; when I try to, it tells me "Impossible to complete the formatting." (my OS is in Italian so I'm translating from italian to english)


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## jamesd1981

Do you know how to get into disk management ?


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## gunzb

yes I'm in it now

http://postimg.org/image/gepwh9qcz/


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## jamesd1981

Is the sd card disc 1 with drive letter p ? If so right click and try formatting from there


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## gunzb

Yes, it's P:\... 

No, it still tells me it's impossible. Now I'm trying to Slow Format (unticking Quick Format).


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## jamesd1981

You could do, but when did you last run virus or malware scans ?

Judging by how problematic this card is, I think it may either be a defective card or your system could have some type of infection.

Also try formatting the card within one of your devices i.e camera, phone etc


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## gunzb

I don't think it's an infection, since all other sd cards and hard-disks work fine. Maybe it's a defective card...  My other devices won't detect the card, so I can't try that. I tried the slow format, but it interrupts after a while. What else can I try?

EDIT HDTune Error Scan still shows like before (all green, undamaged). But the speed test is 2,7 MB/s


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## jamesd1981

This video gives a clear guide to formatting using cmd prompt, but I suspect if all your other equipment works normally this card is likely defective.

http://www.youtube.com/watch?v=d2u2ifAo8ng


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## gunzb

I followed all the steps, but it still gives me the same exact error.


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## jamesd1981

Definitely seems like this card is defective which would explain the original drop in speed as it broke down and has now reached the point of unusable.

You could try running windows check disk, right click disc 1, select properties then tools and run error check.


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## gunzb

I tried to, but it tells me that in order to run checkdisk I need to format the drive, so... nothing again.

Isn't there some drastic way to restore the card to factory condition? Since it's seem to be OK on a physical level.

EDIT Right now I'm trying the "Wipe Data" option of EASUS Partition Manager...


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## jamesd1981

I take you are using a micro sd adapter to connect the card to your card reader, are you sure there is no unlock slider, other than that the only reason I can see why no drive partitioning software can access the card is if it is physically faulty


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## gunzb

Right now I'm using the Samsung card reader that came along with the msd, so there's no need for a SD adapter. I'm using that because it's the only one now capable of reading it at all. 

The easus "wipe data" option didn't work.


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## jamesd1981

I would return the card and get a replacement or refund as it seems to be faulty


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## gunzb

Yes, that does seem to be the only viable option right now.

Thanks for all your help, jamesd1981


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