Speed ​​questionable

Very good price / quality ratio if use is to make sequential, with large files. The CrystalMark test validates a reading at 20 MB / S and write to 16. It is against the disaster if we want to use it for small files. At 512 K, the reading remains very good (20 MB / s), but writing fall to 3.2MB / S. A 4k, reading is 3 MB / s but the writing becomes almost unmanageable with an average 0.035 MB / S. Appraisal: a picture and use common video with a nice storage capacity but impossible USB stick with office use or backup (backup small text files, Excel or similar).