TweakTown posted a review on the ASRock X58 Extreme Core i7 Motherboard

Originally ASRock was to help in the entry to mainstream market while ASUS would concentrate on the high-end and enthusiast market. This worked very well at first, but it is becoming more and more a standard to integrate high-performance features and overclocking into even your basic boards.

The X58 Extreme is one of these boards; it is meant for the Core i7, features overclocking and also high-performance memory support. It is also a subtle jab at GIGABYTE who has their own X58 Extreme mainboard. The X58 Extreme is a scaled down version of the X58 Supercomputer from ASRock, with a correspondingly scaled price.

ASRock X58 Extreme Core i7 Motherboard Review