Is there a time limit on GM norms?

For IMs who want to become one?

Thanks for all the sources! Brilliant answer.

There used to be a time limit of 3 years from the time you got your first GM norm to collect the other 2 necessary to get the title ( you also have to have the 2500 fide rating as well ) . I dont know if this has changed of if there is still a time frame involved. I believe it was the same for IM norms as well. 

 I think the 2500 is still required, but isn't it only two norms they need?

It can be only 2 norms depending on how many rounds they play. Also, winning certain tournies will automatically get one the GM title. Kramnik went from FM ( 2650 ! ) straight to GM ( skipping the IM title ) due to his fantastic result in one of the olympiads. If you win the junior or senior world championship you also get the title. 

I was just wondering how close Pruess was, since he has two norms, but not a 2500 rating yet.