5.5GHz From Overclocked Intel Core i7 965 Extreme

Japanese overclocker "duck" has cranked an Intel Core i7 965 Extreme processor up to 5510.09 MHz, more than 2GHz faster than the chip's stock 3.2GHz speed.  The process paired the chip with an ASUS ROG Rampage II Extreme motherboard, which allows for hardware-based changes to their systems' core frequency, voltage and other parameters in real-time.

In fact, the ROG Rampage II Extreme has a small joystick and other controls physically built onto the motherboard itself, which allow each of the different parameters to be tinkered with.  It also includes an external LCD display to report system frequency and other stats, again in real-time.

As for duck, he's responsible for overclocking a Pentium 4 631 CPU to 8180.4MHz in 2007, for which he holds the record for the world's highest frequency.  This Core i7 test setup included 3GB of DDR3 triple-channel RAM and an NVIDIA GeForce GTX 280 graphics card.

[Thanks Pete!]