Valve has announced some tweaks to its content delivery system that should boost the speed of your game downloads. If you're fortunate enough to have a blisteringly fast Internet connection, you've probably noticed that the current system gets bogged down pretty easily following new releases or during major sales. During the recent summer sale, my downloads were sluggish and paused frequently.
That should be less of an issue with the new system, as its beefier bandwidth threshold will withstand demand spikes. Additionally, Steam will be able to serve content from more locations to reach international users better, and all content will be sent via HTTP. Along with being more firewall-friendly, this will allow the system to automatically take advantage of web-caching proxies installed at Internet providers.
Besides making downloads outright faster, Steam has been tweaked so users don't have to download as much data. With the existing model, if a game file is modified by an update, your client downloads the entire thing -- a real pain if that file is a heifer. The overhauled system improves that by only downloading the file's modified bits. This could also be useful for folks with strict Internet bandwidth caps.
Game creators will benefit from the new system as well, as it has allowed Valve to write new tools for developers and publishers that simplify the process of publishing and updating games on Steam. Users can also expect new client features, such as download scheduling and priorities, bandwidth throttling, and the ability to update a game while playing. Valve will introduce the new system gradually, with DotA 2 being the first game to use it. In the meantime, you can try it out by downloading a 720p game trailer from a Steam store page.