I don’t understand why loading a 1 GB sized project usually takes a way longer time than loading an actual game, e.g. Skyrim, that’s many times larger than the project. For projects, most of the loading time is used to compile the shaders. Doesn’t the game need to compile the shaders as well? If not, then why the quality is as good as the project, in my view?
I think you’ll find that in games like Skyrim the game only loads the surrounding area around you, it does not load the entire map/s. When you launch the editor for your project it has to load the entire projects map not just one small bit so you can scroll through and move around in it and access it freely without lag. Skyrim is very large but it will not render shadows more than 1 kilometer away but if you are in the Unreal Editor with a large mapsize and many shadows it has to load all of them causing a heavy workload on your computer.