Every month, Steam provides an update on the breakout of which platforms are most popular among their gaming customers. For the longest time, Windows 7 was the most popular platform, but Windows 10 has made steady progress and surpassed its predecessor some time ago in becoming the most popular Steam gaming platform.
In August, Windows 10 made up almost half of the systems running the Steam client. Specifically, 48.62% of Steam PCs are running a variant of Windows 10, with the 64-bit version making up 47.44% all by itself. Windows 7 dropped to 34.62% of users, continuing the trend of seeing Microsoft's newest OS become prominent for PC gamers.
Here's a complete overview of the PC gaming systems in use by Steam customers:
There's some wiggle room in the numbers, and so it's entirely possible that Windows 10 was only slight less dominant than it appears here. By that token, however, Windows 10 could have been even more dominant. The most important conclusion to draw is that at least among gamers, Microsoft is making some nice headway in pushing Windows 10 to the masses. Let us know in the comments if you agree that Windows 10 is the premier PC gaming platform.