Fun fact: about 1% of the client startup time is GalacticCraft not loading until it's finished downloading the list of capes. Another 1.5% is CustomOreGen loading it config... and another 50% is GregTech registering recipes for every possible shape of every possible material. Of that 50%, the vast majority is spent looking for recipes to remove in case they already exist. O_o
Minecraft also spends 20% of the time loading textures.