What do the three bytes of data do? Can that be reduced by mapping some of the data into bits? For example the present state of any given LED can be represented by a single bit.
How do you control that many LEDs with a single line? Are you using some sort of serial stream of data?
Is any of the three bytes of data fixed? If so you should be able to store that in fixed memory (e.g. EEPROM or on chip flash.)
Without knowing more about what you want to do it is difficult to offer suggestions.