The GTA:SA loading splash screen of the game (the one with a progress bar and background music) is really slow, because for every progress of the progress bar it's rendering multiple frames, which are affected by the vsync, creating an artificial delay. Also, the fade-in, fade-out and background image change animations delay it even more.
This leads that even if you have a high-end computer running a 2004 game as GTA:SA, it will take at least a few seconds to load, when it could just be a matter of miliseconds.

The idea is to disable the loading splash animation, disable it completely or reimplement it at MTA. This last option would allow higher customization, such as setting our own logo.