Intel K Spec Core i7 875 and Core i5 655 Review
 

These processors are unlocked and meant to be overclocked. This is why both processors reached in excess of 4.5GHz for screen shots and between 4392MHz (i7 875) and 4461MHz (i5 655) for prime 95 stability. This however, took some work to get accomplished as both would easily get close to, or over the maximum clock speeds with just the use of the multiplier for overclocking. In order to really get as high as possible, multiplier and bclock tweaking was required.
http://www.overclockersclub.com/revi...c_i7875_i5655/