Flash drives are connected to a computer using a USB port , which can be found on many devices . Flash drives take their name from the flash memory used to hold files . The majority of flash drives use USB , but some flash drives use other interfaces , such as IEEE1394 ( FireWire ) , one of their theoretical advantages when compared to USB drives being the minimal latency and CPU utilisation that the IEEE1394 protocol provides , but in practice because of the prevalence of the USB interfaces all IEEE1394-based flash drives that have appeared used old slow flash memory chips and no manufacturer sells IEEE1394 flash drives with modern fast flash memory as of 2009 , and the currently available models go up only to 4 GB , 8 GB or 16 GB , depending on the manufacturer .