Difference between Sails.lift() and Sails.load()

I'm trying to make some test on a Sails app. So beforeEach test I need to lift my Sails like this :

// Reset database before each test
beforeEach(function(done) {

  // Get instance of Sails
  sails = Sails();

  // Lift the app
  sails.lift({
    // configuration for testing purposes
    hooks:{
      // Don't call Grunt
      grunt:false
    }
  }, function(err, server) {

    if (err) return done(err);

    // Should have heartbeat in global variable
    // But is not in global
    // So we hack it to get heartbeat
    heartbeat = sails.services.heartbeat;

    done(err, heartbeat);
  });
});

But I see that is a little slowly. So I saw some people use Sails.load(). Does really have a difference between Sails.lift and Sails.load ? if yes, which one ?

Thank's !