Mine is set up to report the whole 2 gigs... I still usually get supervillins and others about that size, I haven't had one bigger than 5 million steps yet.
But if you answered yes to this question in the console.. you will get bigger ones...
Allow receipt of work assignments and return of work results greater than 5MB in size (such work units may have large memory demands (no/yes) [no]?
By default, the client gets assigned only WUs that won't need a lot of network bandwidth or ressources.