I downloaded from the most original source I could find: https://www.heise.de/download/product/h2testw-50539/download
It is prudent to be wary of where you download from. I first found out about this program from
and they reference the German distribution.
To Herald Bögeholz who wrote the Program H2testw, Thank You!
To c’t Magazin für Computertechnik, Thank You!
To www.heise.de for hosting the download of the programme, Thank You!
I just downloaded (clicked the green Download button) and then did a virustotal scan. You should be able to reproduce the test.
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2018-04-19 18:59:56 UTC
Zip archive data, at least v2.0 to extract
ZIP compressed archive (100%)
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This program may not be the fastest, but it is thorough; I have never seen it fail to detect a bad card. Some claim it detects a few “good” cards as bad, but I am wondering if those claims were from sellers of counterfeit cards.
NOTE: this does write to almost the full capacity of the flash, so it does use up one of the devices write lifetime.
You don’t need to install it, just unzip the file. No need to run from administrator account, it just creates files and reads them. But it doesn’t just write a simple pattern, if you are interested see below.
When the program starts, click on the “English” button unless you prefer German. Then select the drive to test. Then click write+verify and go do somthing else for a while.
Basics of operation: start with a freshly formatted (quick is fine) card. h2testw will choose a seed for a PRNG (Pseudo Random Number Generator). It then creates 1GB files using the stream of output from the PRNG until the device has less than 1GB, then creates the last file to fill the device. Note: each of these files are different and “apparently” random. Then it resets the PRNG seed to what it used before, so it can recreate the same “pseudo random” stream a second time. But this time it reads the files and compares them to what was written before. If there are differences it reports how many difference there were. On a good card the report will look something like this. The header is mine for documenting what I was testing. Note it can’t test the part that was part of the file system, that is why it gives the warning about not testing the whole capacity.
All testing done with Win10 on MicroCenter B638 USB3 port to Plugable USB 3 Hub to Rocket USB3 dual card reader/writer
Samsung EVO+ 32GB class 10 UH1 microSD
–h2testw results follow–
Warning: Only 30515 of 30516 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 23.6 MByte/s
Reading speed: 76.0 MByte/s