10.9.4, Xcode 5.1.1, targeting iPads only.
When a developer is ready to submit an IPA to the App Store, you select Product -> Archive and follow the prompts.
On my MacBook Air, Core i5, with 4GB of RAM, this takes a lot of time (15 mins). It goes through a lot of compilation, several phases, 500+ files.
I assume what is happening here is that it is building for each platform, iPhone, iPad, iPad Retina, etc but I really don't know.
What happens during this phase, technically?
Are there ways to speed this process up?