What is flash memory? Flash memory is made up of arrays of floating gate transistors. It has very fast program time but a slower erase time compared to EEPROM. The NAND type is primarily used in memory cards, USB flash drives, and solid-state drives, and similar products for general storage and transfer of data. NOR flash memory is also often used to store configuration data in numerous digital products. Flash memory can withstand high pressure, temperature, and much more, making it one of the most durable memory options. In addition to being non-volatile, flash memory offers a read access time as fast as dynamic RAM.