It seems that ASUS is working on a new series of graphics card that will surpass clock frequencies as you know them. Over at behardware it is reported that Asus has announced the release of two new graphics cards based on the Radeon HD 4890 and the GeForce GTX 285.
By itself pretty snazzy and fast cards yet, what ASUS plans is an improved version of the stock cards, then apply better components in the hope they will function at lower temperatures. As such offering better clock frequencies.
Behardware: Asus is highlighting the use of multilayer polymer capacitors from Fujitsu, that are already used in some high-end motherboards. In particular they give an ESR that is lower than average and are therefore able to function for a long time, even at high temperatures.