2 types of memory, flash and ram.

flash stays in after you switch off.

ram will fade away after you switch off.

you load from disk to replenish the ram, or change the flash.

the performance/backup split on the save page 2 refer to these distinctions.

you can load and save all sections or some sections. Some sections can be split into even smaller loads - single composer, single sound, single song, single panel memory, single custom style. Also 3 bank or all banks panel memory.

Why?

mainly cut down on load time.

if you easy record from preset sounds and styles you don't need to save composers or pads or sound memories.

if you just want new pads, it is a waste of time overwriting composers, sounds, panel memories and effects.

If you load new styles you need composers or custom loads.

etc etc.

the flexibility this gives means you can move and combine information from different files and saves, and plan a playlist load with the maximum of information to play a large number of songs with the minimum of disk loading downtime by selectively loading only the information required for the next batch of playing.

if you don't want to bother with all this, just do performance saves each time....
(see pages 18 and 19 among others )