A common performance optimization idea that segregates loadable zones by low-impact medium, allowing pre-loading expensive content during travel time.
A typical example is an island chain, however mountains and deserts can work as well.
The idea is to segregate high-density content into compact zones which won't be loaded all the time, but only when near the zone: the inter-zone travel is through low-density content.
Typical gameplay scenario:
1.Player leaves Zone A(unload all assets).
2.Player in inter-zone low density area.
3.Player is near Zone B(load all assets).
4.Player enters Zone B preloaded with content, because of travel time in 2-3.
This works especially well if player has a hard disk drive which is used by multiple programs: this hides the drive seek/read latency by background preloading when player travels toward Zone B. If player has a fast SSD and plenty of RAM the performance benefit is smaller, however preloading is always faster(and archipelago facilitates this)