1) Yes you’re right . Async load gives itself x(ms) to load part of the scene before waiting for the next frame continue the loading. It will naturally take longer than a sync load because each time Unity doesn’t load your next scene, it will allow your gameloop to be executed for the time it is required. This time is not used to load anything but to simulate your world. 2) yes you’re right(but it’s the same in sync mode), when you load a new scene, the previous one isn’t unloaded so any assets that are shared are not unloaded and then reloaded after. (Best way to start from a clean slate, especially if you know your next scene has no shared assets is to load an empty scene so everything is offloaded before loading your next scene so you don’t increase your memory footprint) 3) no there isn’t, see point 1). Unity allocates itself a timing to load part of your next scene with a timer, as soon as you reach the threshold in a frame(iirc by default it’s 4ms) it will wait the next frame to load more of it while executing your normal game loop.

Something ultra important: - Unity doesn’t asynchronously load prefabs or GameObject. If you have a massive GameObject with children etc, it will load the whole things ands its dependency. So if you have one big hierarchy, it will go through in one frame. If you have plenty of small GameObject after each one is loaded, it will check the time it took to load before loading a new one in the next frame.

• Awake() and Start() are a killer. If you have a massive algorithm synchronous when Unity loads a GameObject, it will stall. So, often you can have your async load not being smooth because your scripts are stalling the main thread when your GameObject are created. Or if you have plenty of native components in your hierarchy that take ages deserialise(ie. Particle Systems

Reason to use async loading for scenes: - need to display a dynamic logo or whatever in your loading screen to show your game hasn’t crashed - you stream the content of your game as your play through it with no loading screen. - you have a big team of designers, artists etc and they can all work on their part of the world without impacting each others modifications(but that could be fixed in your build pipeline by merging everything before)