From the EF Poser 7 page:

"Render in a Separate Process: FireFly now has the option to run in a separate process from the application, which can yield performance advantages when rendering highly complex scenes. FireFly also lets your system manage memory more efficiently and provides better system stability due to the separation of rendering tasks."

So, it's a seperate process from the application, but you still have to finish rendering to do anything else within Poser?  Or is this so I can start rendering, kill Poser and have resources free for other things?  I just got Poser, boxed, yesterday and haven't played with it much yet...