Possible counterfeit 512gb sandisk extreme micro sd card

i bought a sandisk extreme 512gb micro sd card (true capacity 481.3GB) designed for 4k video, however i only get an average write speed of 2.4MB/s and about 61MB/s reads on an app i bought called “True SD card capacity/Speed Test Pro” .

it passes all the tests up 35% capacity using this app, so it doesn’t look like it’s losing data.

i thought it was a fake micro sd card when i noticed the disney+ app downloaded video to the micro sd card and then displayed files only containing a few megabytes or kilobytes that were unplayable, and sometimes crashing the disney+ app, but it doesn’t seem to be fake according to the testing app, just slow.

i am currently running another test using the mentioned app up to 52% capacity but it’s going to take days.

what kind of write speeds am i supposed to be getting?

is it possible that it is a counterfeit sandisk micro sd card and that it’s designed to fake the passing of the tests?

i’ve tested up to 77% capacity and it reports no errors, with 2.4MB/s writes and 60MB/s reads.

it definitely doesn’t seem to be losing data, just extremely slow.

is this a new breed of counterfeit micro sd card where they’re just extremely slow?

i’ll reply to this post with progress.

i get 3.4MB/s writes on a different smartphone using the same app

using a dongle attached to a pc, i get just under 20MB/s writes

Hi @isitfake,

In order to check speed of your flash drive we recommend you to please use below software to make a general assessment of your testing.
• To download the software, please refer to below link:

Windows: CrystalDiskMark
Mac: BlackMagic utility

• Run the file and Install the software by following the installation wizard.
• Once the software is installed, please locate the “CrystalDiskMark Application” icon on the desktop
• Double click the icon and then select the SanDisk flash drive in the Device box.
• Run the speed check read & write speed.
• Once this process will complete, share screenshot of test results with us on support@sandisk.com

i plugged it into my pc and a program called omacp was installed without my knowledge, of which was infected from my android phone.

i couldn’t remove omacp from my phone so i did a factory reset, but i think it’s still infected, and i’m unsure if i’ve completely removed it from my windows pc.

i’m not sure if it was the new microsd card or the sim card that was originally infected, or perhaps it was infected remotely via text message (i had a lot of spam texts soon after i put in the sim card).

Hi @isitfake,

Please refer below link to contact respective team to help you with trouble shooting steps:

Hi @isitfake,

Please refer below link to contact respective team to help you with trouble shooting steps:

extreme would give you at least 35-40mb/s in real life, unless you’re using a really outdated pc and reader.
with USB 3.0 it never fall below 35mb/s write and 90mb/s read.

DiskPart is an integrated Windows disk partition utility. You can run it using the Command Prompt, and it is an easy way to make the fake microSD usable.

First, open This PC. Make a note of the microSD card drive letter.
Input command into your Start menu search bar, select the Best match, then right-click and select Run as administrator.
Now, type disk part, then list volume.
Input select volume [your drive letter]. You’re now going to shrink the drive to the real memory size. Please note the following command works in megabytes. For instance, if you want to decrease the drive size by 1GB, you would type “1000.”
Input shrink desired [number of megabytes], and press Enter. For instance, if you bought a 512GB drive but its capacity is actually 8GB, you could type “shrink desired 504000.” The command will decrease the capacity by 504,000MB (504GB), leaving 8GB of working memory shagleazar.