To find the real capacity of nand flash memory storage chips, the best software that is “free” is H2testw.
To learn more read: H2testw 1.4 – Gold Standard In Detecting USB Counterfeit Drives. It has all the information you need to understand how the program works and where to get the download.
The software was written by Harald Bögeholz. It is copyrighted, but is offered to people to test their nand flash memory devices. The article also explains why it is the best testing software available and why it is recommended. People use it to test usb pen sticks, memory cards and mp players.
Update 20091023: If you find you have a fake capacity flash memory item and want to repair it, please consult the new FAQ at FixFakeFlash Inspectortech for important information on repairing fake flash memory items before you attempt to repair.