When do cards go to the graveyard?

[Xenocide]

If I have 6 cards in my graveyard, cast infernal tutor, and in response to infernal tutor cast cabal ritual, does the cabal ritual give me 3 or 5 (with threshold) mana? In short, does infernal tutor go to the graveyard when it is cast, or when it resolves, or at a different time?

[Bryant Cook]

3 Mana, cards go to the stack and resolve before going to the graveyard.

[Xenocide]

Well that sucks. Thanks wastedlife.