Not all SD Cards are Equal

Following on from my comuting on the cheap trend. Some time a go I bought a cheap 32GB SD card from the well known on-line shopping site. It didn’t work very well in my Android ‘phone, so I bought a smaller and more expensive one. recently I decided to test it, yes I still kept it even knowing it was a pile of crap. I downloaded f3 from http://oss.digirati.com.br/f3/ and ran it on the card, output below.


./f3write /run/media/mikee/77ab21a2-818a-472c-81cf-f8a73e9c3de7
Free space: 29.94 GB
Creating file 1.fff ... OK!
Creating file 2.fff ... OK!
Creating file 3.fff ... OK!
Creating file 4.fff ... OK!
Creating file 5.fff ... OK!
Creating file 6.fff ... OK!
Creating file 7.fff ... OK!
Creating file 8.fff ... OK!
Creating file 9.fff ... OK!
Creating file 10.fff ... OK!
Creating file 11.fff ... OK!
Creating file 12.fff ... OK!
Creating file 13.fff ... OK!
Creating file 14.fff ... OK!
Creating file 15.fff ... OK!
Creating file 16.fff ... OK!
Creating file 17.fff ... OK!
Creating file 18.fff ... OK!
Creating file 19.fff ... OK!
Creating file 20.fff ... OK!
Creating file 21.fff ... OK!
Creating file 22.fff ... OK!
Creating file 23.fff ... OK!
Creating file 24.fff ... OK!
Creating file 25.fff ... OK!
Creating file 26.fff ... OK!
Creating file 27.fff ... OK!
Creating file 28.fff ... OK!
Creating file 29.fff ... OK!
Creating file 30.fff ... OK!
Free space: 0.00 Byte
Average writing speed: 913.84 KB/s
[mikee@saxicola f3-2.2]$ ./f3read /run/media/mikee/77ab21a2-818a-472c-81cf-f8a73e9c3de7

SECTORS ok/corrupted/changed/overwritten
Validating file 1.fff ... 414704/ 1682448/ 0/ 0
Validating file 2.fff ... 0/ 2097152/ 0/ 0
Validating file 3.fff ... 0/ 2097152/ 0/ 0
Validating file 4.fff ... 0/ 2097152/ 0/ 0
Validating file 5.fff ... 0/ 2097152/ 0/ 0
Validating file 6.fff ... 0/ 2097152/ 0/ 0
Validating file 7.fff ... 0/ 2097152/ 0/ 0
Validating file 8.fff ... 0/ 2097152/ 0/ 0
Validating file 9.fff ... 0/ 2097152/ 0/ 0
Validating file 10.fff ... 0/ 2097152/ 0/ 0
Validating file 11.fff ... 0/ 2097152/ 0/ 0
Validating file 12.fff ... 0/ 2097152/ 0/ 0
Validating file 13.fff ... 0/ 2097152/ 0/ 0
Validating file 14.fff ... 0/ 2097152/ 0/ 0
Validating file 15.fff ... 0/ 2097152/ 0/ 0
Validating file 16.fff ... 0/ 2097152/ 0/ 0
Validating file 17.fff ... 0/ 2097152/ 0/ 0
Validating file 18.fff ... 0/ 2097152/ 0/ 0
Validating file 19.fff ... 0/ 2097152/ 0/ 0
Validating file 20.fff ... 0/ 2097152/ 0/ 0
Validating file 21.fff ... 0/ 2097152/ 0/ 0
Validating file 22.fff ... 0/ 2097152/ 0/ 0
Validating file 23.fff ... 0/ 2097152/ 0/ 0
Validating file 24.fff ... 0/ 2097152/ 0/ 0
Validating file 25.fff ... 0/ 2097152/ 0/ 0
Validating file 26.fff ... 0/ 2097152/ 0/ 0
Validating file 27.fff ... 0/ 2097152/ 0/ 0
Validating file 28.fff ... 0/ 2097152/ 0/ 0
Validating file 29.fff ... 0/ 2097152/ 0/ 0
Validating file 30.fff ... 18320/ 1896544/ 0/ 0

Data OK: 211.44 MB (433024 sectors)
Data LOST: 29.71 GB (62299248 sectors)
Corrupted: 29.71 GB (62299248 sectors)
Slightly changed: 0.00 Byte (0 sectors)
Overwritten: 0.00 Byte (0 sectors)
Average reading speed: 14.89 MB/s

Yep, of the claimed 32 GB it managed to corrupt 29.71 GB. None of the test files were uncorrupted, not a single one. Also note the that the write speed is very slow.

F3 is also on GitHub at https://github.com/AltraMayor/f3

This entry was posted in Uncategorized. Bookmark the permalink.