The max writing speed is 15x faster than a standard flahs drive (4MB / s)., That gives a maximum speed of 60MB/s which varies depending mainly on the size of the file,
NOTE : The SanDisk Ultra line does not ensure a stable sequential write speed (dont have the write speed on the packaging). If you want high-speed sequential write, you must switch to SanDisk Extreme line.
The file system and the cluster size are also factors that influence the speed of large files. Test as follows:
CAUTION : This will remove all the contents of your USB flash driv e, be sure to select the correct removable drive letter and make a backup if necessary.
Download the SD Card Formatter Sofware link: https://www.sdcard.org/downloads/formatter_4/eula_windows/index.html
Disconnect any USB device, and insert the USB flash drive, then open the “sd card formatter”, click on “Option” and select “Format size Adjustment: ON”, and proceeds formatting.
The USB flash drive will be formatted in exFAT file system, You can make a new speed test now, I recommend the CrystalDiskMark: http://crystalmark.info/download/index-e.html