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Original topic:

Galaxy Book 12 Low micro sd speed

(Topic created on: 01-12-2017 03:22 PM)
First Poster

Hi. I have a Galaxy Book 12 SM-W720 and a Samsung EVO+ 256GB UHS-I microSDXC U3 Memory Card. The microsd card is rated at 95/90 MB/s read/write speed. When I insert the micro sd card in the book 12 slot the speed is very slow. 64 MB/s reading, 18 MB/s writing (tested with CristalDiskMark). If I test the same card with an external USB reader the speeds are great. I've tried recovery to factory, updating drivers, different micro sd cards and couldn't fix the problem. Could anybody who has the same tablet measure your micro sd speed with crystaldiskmark? The software is free. Please share your results. Thanks

First Poster

Yeah, I’ve had the same issue. The problem is that Samsung, and pretty much every tablet and phone manufacturer nowadays, do not report information on the specifications on their as card readers regarding the class rating or speed. I’m guessing that the rating is not UHS-1, as my faster cards NEVER get the speeds anywhere close to you would see on the usb 3.0 adapters they come with. Don’t even hope for UHS-II or higher anytime soon...


Hi duendetuc,


can you please have a look in the device manager and find out, what's the name of the Micro SDcard reader?


I own the same device and want to buy a Micro SDcard, but of course I don't want to buy a Micro SDcard, which couldn't use it's full potential.

So, I'll try to figure out, what's the maximum speed, the reader supports to buy a matching micro SDcard.


Thanks for your help!


PS: Any other user of the Galaxy Book could help, too!

And of course, if you help me, I'll help you and make a benchmark with crystaldiskmark :winking-face:
First Poster

Same Issue here... Slow performance on internal SD card.


I have Samsung Galaxy Book 12 LTE (Model No: SM-W728) - Windows 10 fuly updated.


Just purchased a "Samsung Mobile UK 256 GB 95 MB/s Class 10 U3 Memory Evo Plus MicroSD"  from Amazon (Sold by Amazon and listed from Samsung Mobile UK so confident it's genuine). The card claims "up to 95 MB/s read and 90 MB/s write".


I've formatted as NTFS and the perfrmance is not what I'd hoped for. Transfering a mix of office and media files I get around 8-20MB/s write. 


The latest version Crystal Disk Mark doesn't show the disk at all.


Atto Disk Benchmark shows mostly low 20's (MB/s) write until i/o size over 32MB and then the best write speed when at 64MB is 40MB/s. Read speed much better across the board at 75-80MB/s.


Testing using AJA System Test (simultaes write/read of uncompressed 1GB video file) I get 39MB/s write / 77 MB/s read. 

It came formatted as exFAT - and I was getting slightly faster write on the AJA system test at 45MB/s - still nowhere near what it could be though.


Windows Device Manager shows the SD Card as "Generic EE8QT SD Card" (as I don't plan to treat it as a removable disk I've also enabled write caching in the device's properties>policies).

First Poster

im the manual it is said that only FAT file system memory cards are supported