GPU Tweak is ROG's new graphics monitoring, tweaking, overclocking, recording and general do-all software developed by ASUS VGA and ROG teams. It's free and you can use it for any graphics card (officially from GTX 500/HD 6000 series onwards, but older cards are compatible) although ASUS and ROG cards have a few unique features reserved for themselves. You can download the official release version, 188.8.131.52, here.
You've also probably noticed the above main banner on our site to a page that takes you through all the features, and if you're a forum member you'll have seen our dedicated GPU Tweak forum where you can discuss the software as well.
JJ from ASUS North America and myself have also made some videos detailing and explaining GPU Tweak, so check them out below and let us know your thoughts in the forums!