Steam beta client update adds FPS counter
Glory in your superiority as a member of the Master Race with a handy new Steam client feature.
Valve has added a frame rate counter overlay in its latest Steam beta client.
This means that you can quickly and simply check what FPS a game is running in without having to fire up FRAPS or another third-party tool, potentially eating up system resources.
Checking your frame rate is a good way to see how your system is handling various graphics options, so you can tailor your experience to match your equipment for the smoothest gameplay experience. (Alternately, it can be used to enable a smug feeling of superiority over console owners. We don't recommend this course of action.)
Beta client features almost always make their way to the general release, so unless you're in a major hurry to check your frame rate performance you can probably sit tight and wait, Otherwise, opt in for immediate access.
You can see what other features and tweaks were made over at the Steam Community announcement.