Oh please continue
I do it all the time. Mostly for tests; And mostly for very complex scenes.

Useless to recalculate everything on screen to see how a light change will be in a corner. Or just change hair on a single figure.

Lots of RAM helps of cource.

The more complex the scene, the more time you gain for an area render.

Just to refine my answer: Full render or area render.
Both times everything gets loaded.
But, the actual render time = calculations = gets reduced to your area.

But to do those calculations, Poser has to know what is around that specific area.

Poser 1, 2, 3, 4, 5, 7, P8 and PPro2010, P9 and PP2012, P10 and PP2014 Game Dev
"Do not drive faster then your angel can fly"!