Screen Display Time vs Background Activity

I’ve been testing this out, and I seem to get different results.
Some screens will have more to think about, depending on anything and everything.

For one screen I am using network.download(), which can have different loading times, if the external server is not responding.

So here’s my question,

Does a screen load into the device when everything has loaded into memory?
Or does it prefer to load individual elements, as the device can handle?
Or is it a mixture of both?

I ask this since I’ve noticed a blank/black screen on occasion, then the screen loads.
And oddly enough, I’ve noticed the visual assets load, while other background logic is running.

I haven’t narrowed in on everything yet, but I did want to ask if there’s a hierarchy of loading logic. [import]uid: 154122 topic_id: 28376 reply_id: 328376[/import]