So, with a little grunt work, we were able to establish a stable overclock to 4.0 GHz on our Core i7 920 processor, maxing out at 190 MHz FSB using a 21x multiplier (Turbo Mode). This represents a 50% boost in clock speed with absolutely no price increase. However, while overclocking does deliver better performance for free, it does come at a price, power consumption. All of our overclocked systems were using a 1.325V vCore and 1.7V vDIMM. Here you can see how much upping your processor speed also ups your power bill.
As you can see, under full load, there is a sizable difference in terms of power consumption between our stock speed chip and our highly clocked and over-volted chip. This 50% boost in clock speed also requires 48% more power under full load. While our systems are still fairly low in terms of overall power usage for the performance which is offered, this is something to keep in mind when you start to unleash your 920's overclocking options.