a10tm - a20m... what difference???

[alfvv12]

hi.
the a20m has another design against a10m. ok. but what is the difference?
.

same board gt2560 v4. 0....

the a20m seems to have a power loss functuon for resuming printing.

but where is the memory chip for this function? same board, same extruder, same steppers...

i dont realize the difference...