F3

F3 (Fight Flash Fraud, or Fight Fake Flash) is an open source, cross platform H2testw clone. It fights fraud by creating a series of files to readable portions of flash memory and does calculations on current read/write speed. It can be useful in determining how much usable storage is actually present on a a device, despite what is on the devices label.

Test write speeds
In order to do a true read test, F3 must first create a series of files in the available free space on the device:

Depending on the size, free space, and write speed of the device, his could take quite a while. Whenever it is finished, it will be possible to test read speeds.

Test read speeds
After the write test has finished, read speed can be tested using the following command:

F3 will read though the available files and calculate if there are any consistency errors. It will also calculate read speed. It is quite normal for read speed to be faster than write speed, especially on removable media.