Valve makes a good case for its hybrid threading model, although it's hard to argue against using the most appropriate threading approach for a given task. Creating a programming framework that allows that kind of flexibility was apparently very difficult, but in the end, Valve says it will enable games that competitors who don't make the same investment in multithreading simply won't be able to match. Hybrid threading has also proven to be an asset in the company's work with Microsoft's multi-core Xbox 360 console, and Valve says it sets them up nicely for what they believe is a "post-GPU" era looming over the horizon. Interestingly, though, Valve noted that its model isn't particularly applicable to the PlayStation 3's Cell processor.

Valve intends to roll out hybrid threading enhancements in the next major Source engine update, which will be released before Half-Life 2: Episode Two ships. Those enhancements won't include the richer visual simulations, smarter AI, or more complex physics that are possible with multi-core processors, but dual- and quad-core systems should see a performance boost with Valve's existing Source-engine games.