I've used both gephi and cytoscape, i have about 2 million nodes with about 3 million edges, it's hard to visualise at once. however i've reduced the graphs to

I've used both gephi and cytoscape, i have about 2 million nodes with about 3 million edges, it's hard to visualise at once. however i've reduced the graphs to only sub networks with more than 5 connections, the remainder is about 600k, which is still painfully slow to visualise