The Steam Hardware & Software Survey now offers the June results showing the hardware being used to play games on Valve's service (thanks VG247). These results reflect jump in the use of newer hardware, and they kick off with the following explanation of how this is in part because they've addressed a bug in the system:

There was a bug introduced into Steam's survey code several months ago that caused a bias toward older systems. Specifically, only systems that had run the survey prior to the introduction of the bug would be asked to run the survey again. This caused brand new systems to never run the survey. In March 2012, we caught the bug, causing the survey to be run on a large number of new computers, thus giving us a more accurate survey and causing some of the numbers to vary more than they normally would month-to-month. Some of the most interesting changes revealed by this correction were increased OS share of Windows 7 (as Vista fell below XP), the rise of Intel as a graphics provider and the overall diversification of Steam worldwide (as seen in the increase of non-English language usage, particularly Russian).