Gamepyre posted a review on the Intel Core 2 Extreme QX6700 Quad Core CPU

The user that can most benefit from the QX6700 is for people that are high-end gamers and for those that use multimedia applications. As HD-DVD and Blu-Ray movies move into the general PC market, the need for high power CPUs like the QX6700 will likely grow. H.264 content is very CPU dependent, bringing high-end single core CPUs to their knees. The QX6700 is expensive, but you get what you pay for. The target market for the QX6700 is for the high-end enthusiast willing to pay a grand for their CPU and for the OEMs needing a Christmas season refresh of their computers. In that respect, the QX6700 does what Intel wanted it to and is an excellent choice for those wanting the absolute best in multimedia performance. The 975XBX2 is the second iteration of Intel motherboard, designed to work with the Core2 CPUs.

Core 2 Extreme QX6700 Quad Core CPU Review