We received this press release from Valve Software, announcing that the Half-Life 2 developer has hooked up with AMD to create a 64-bit version of the Source Engine. Available through Steam right now are 64-bit versions of Half-Life 2 and Lost Coast. Steam automatically knows what OS you are running (so yeah, you need Win x64 for this) and will launch the appropriate game build.

"Bringing the Source technology to the AMD64 processor platform is an important step in the evolution of our game content and tools," said Gabe Newell, Valve's co-founder and president. "This investment in future processing will allow us, and third party developers working with Source, to push the boundaries of the gaming experience." "AMD Athlon 64 FX processors are targeted for systems designed to provide the ultimate experience for a new generation of power users running demanding applications " said Bob Brewer, corporate vice president, Desktop Division, AMD's Microprocessor Solutions Sector. "Combining the performance of AMD64 processors with the 64-bit version of Valve's technology results in advanced and powerful games. This winning collaboration brings customers an amazing product based on the best of AMD64 technology and Valve's software development."