What is the fastest computational graph theory package? 
What is the fastest computational graph theory package with respect to executing algorithms and computing graph theoretic data?

I am aware of this related question, which requests graph theory software geared towards drawing graphs and getting data on them.  I don't care about graph drawing, or user interface in general, so much as the speed of the analysis and the variety of algorithms available.  Basically, I'm trying to find the graph theoretic analog of MAGMA.  (Note: I do know magma has some graph theory, but it is very limited.)
I would prefer the software be free if possible, but I may be able to pay depending on the price of a student license.

I've been using open source library LEMON (http://lemon.cs.elte.hu/).
I have compared it to other libraries for my application and this is the fastest one.
