With today dawning, Valve has finished converting their multiplayer Source engine games to the new SteamPipe system. This involved Day of Defeat. Source, Counter-Strike: Source, Half-Life 2: Deathmatch and Team Fortress 2.

With the new update, these games have been given the blessing called VPK (Valve Pak) storage system, which could be familiar to you from Portal 2 and the Left 4 Dead games.

To spare you from the technical details, with these files, the major imporevement is that games are supposed to load faster (well we'll see...) than with the old GCF (Game Cache File) system. VPKs are chunked (bye-bye 8 GiB big Team Fortress content file) and they have a seperate file index.

This all contribute to improving loading and updating times. From now on, it is said that Steam will have to download less overhead bytes when an update happens and it will be less harddrive and CPU consuming.

How does this affect you?

When starting these games, you will be prompted to convert the game before you could start it. This happens automatically and is moderately fast: your custom download content will not be lost (it will be moved to a specified folder) and then, Steam will begin to repack the official stuff. (Be advise, the client WILL lock up during this process and you'll be unable to chat.)

Then, after everything is done, you'll be able to find a game. The content will be moved to the common folder under SteamApps (just like where Portal 2 and Left 4 Dead resides).

But be warned. Custom content might (in case of custom HUDs put in the scripts and resource folder of a game, will) break and you will have to reinstall them.

This not yet affects Garry's Mod. Garry had already implemented the loading of SteamPiped Source multiplayer content into the game, and GMod itself is still using the VPK format.

For further reading, head here.