No matter how good/fast your computer is, Minecraft+ 100 mods is a slow thing. Minecraft's engine is Java, and thus it isnt optimized for gaming and heavy graphical content. The more you explore from the world, the more time it will take to load up. Once i travelled 7 000 blocks in one direction on creative(FTB Ultimate), the other day it took 30-40 minutes to load up. Thats Minecraft..... Awesoe the more redpower, and other mod added laggy items you use/place the more fps lag you will have.