"With Guy's expertise, the QX6700, along with the ASUS R.O.G Commando motherboard, cooled by nothing but air, reached a maximum (non-stable) frequency of 4241MHz – at this clock speed the system was so unstable that even taking a screenshot was impossible and we had to take a photo of the screen with a digital camera. The maximum stable frequency which allowed us to take a screenshot and even get CPU-Z validation is 4171MHz – a world record for an air-cooled QX6700."
Check it out over here.