According to Valve Corp.’s Steam Hardware Survey, Mac computers already comprise 8.46 percent of Steam clients in the software’s first few weeks of availability.

Steam is Valve’s popular game software delivery service. Steam operates on millions of PCs around the world, and in mid-May the company released a Mac version of Steam. With it, Valve has produced Mac-compatible versions of its popular games including Portal and Half-Life 2, and promises to treat the Mac equitably with the PC going forward. Steam is used by third-party software publishers, some of whom are also publishing games for the Mac.

Valve’s Steam Hardware Survey is compiled from data collected from individual Steam users. “The survey is incredibly helpful for us as game developers in that it ensures that we’re making good decisions about what kinds of technology investments to make,” reports Valve. Data collected include the type of CPU, graphics hardware, memory configuration, graphics capabilities, numbers of CPU per machine, and operating system type, among many other items.

With Steam’s arrival on the Mac in mid-May, the May Steam Hardware Survey is the very first to feature Mac-specific information. Macs are identified in the report as either running Mac OS X 10.6.3, 10.5.8 or 10.6 – 6.73, 1.40 and 0.33 percent, respectively.

The majority of Steam users – 32.89 percent, overall – use Windows XP running in 32-bit mode. Windows 7 in 64-bit mode makes up the second most-popular operating system with 24.77 percent.