I saw this post on r/feedthebeast and I thought it could be a good idea, I don't know if it was already suggested or if it is possible.
"When you launch the game it loads and checks everything that the mods add - but this does not need to be done at every single startup.Do it once, and save the result. Save the item/Block IDs somewhere, what ever else is needed too. And upon startup just check if anything has changed - if not, use the already existing data."