[.net] c# binary serialization memory usage

So I have a project that I'm toying with really and I've hit a major problem. The project is a hacking sim game using winforms. I have my program generate a massive amount of data about virtual people and computers and then I save the data to a file using binary serialization so that the player can play again later. If I set the program to create 50k people, it uses about 250MB of ram. When i go to load the 77MB save file, the amount of memory required to load the data explodes to 1.38GB. Also the program doesn't dispose of any memory after the loading is done. What could be causing the ballooning of memory usage? I've got rudimentary logging in place and to my knowledge there is no data duplication or anything like that occurrin. I'm really stumped.

Edit: I suppose I should note that I am a bit of a newb when it comes to serialization. Also of note is that I have a single game class that I serialize to a file. This Class contains several lists that cross reference each other. I am under the impression that the .net binary formatter handles this appropriately, am I wrong?

What method are you using to serialize/deserialize? By default .NET does not support circular references. Try using DataContractSerializer while setting preserveObjectReferences to true.

Never assume anything when comes to serialization. The reality is that the seralizer has no idea what you really want, so it tires to do the best it can. With the situation you have, I would create my over seralizer.