At out-of-the box speeds, there is only a slight difference between the Asus HD 6970 Direct CU II and a vanilla Radeon HD 6970. At only 10Mhz faster, that's not much of a surprise.
Things do pick up once you get going with the overclocking, but we were disappointed by how quickly we hit the limits of this particular card's chip.
DirectX 11 tessellation performance
DirectX 11 gaming performance