"model memory" simply means that you can store the data for that many aircraft in the radio, thereby allowing you to control 6 or 8 aircraft with that one radio. When you change airplanes, you just change the memory number in the radio, and all your setups change to that plane. I think what you are refering to is a radio that uses the synthesized module. JR and Futaba both have it, I believe. It allows you to select which frequency you want to use, instead of being locked into one particular channel. Comes in really handy if you fly at a field with lots of other people.