It is my understanding that there are a couple factors in how long it take to load up a scorm. Of course, some of it has to do with how the server stuff is set up and the amount of memory the computer opening it has but the biggest factor is the size of the scorm.
I have scorms that are small (less than 10 MB) and some that are very large (more than 300 mb). The large ones take a longer time to load than the small ones. SCORMs with video and audio take longer to load. There are things you can do in some authoring tools to minimize this (in Captivate you can select the amount of the project loads before view) but it all comes down to the size of your package and the capacity of your computer.
You could try breaking big modules into smaller parts.