The subject says it all what do you guys think is the fastest and more efficient way to store data using an arduino. Everything is on the table from EEPROM to save in some external RAM or SD cards. I am looking for something that can save 1 or 2 'char's in less than 10 ms. The amount of data is more or less 600 000 bits :p
I know that this look kinda impossible for a device like arduino but just want to know your opinions.