The main difference between EEPROM and flash memory is that EEPROM can `` write '' to any byte of memory , at any time . Although technically a type of EEPROM , the term `` EEPROM '' is generally used to refer specifically to non-flash EEPROM which is erasable in small blocks , typically bytes . Because erase cycles are slow , the large block sizes used in flash memory erasing give it a significant speed advantage over old-style EEPROM when writing large amounts of data .