Crashes and low FPS with many mods

I've done lots of experimentation, and came to the conclusion that the mods Resonant Induction and ICBM are causing the crashing (or at least the crashes don't happen when these mods are not present). However, in the Yogscast Complete mod pack ( http://www.atlauncher.com/pack/YogscastCompletePack/ ), both of these mods are present, and not only does the game not crash, but there is significantly higher FPS and better chunk loading, even though there are more mods.

Is there a...

Crashes and low FPS with many mods