Extreme cooling is a must for any sort of extreme overclocking. Kingpin cooling looks to provide the solution with liquid nitrogen heatsinks designed for extreme overclocking. Using said heatsinks, overclocking expert managed to take a GTX 690 all the way up to 1547MHz which I believe is a new world record.
Originally he had tried for 1600MHz but it wasn't stable so he backed it off to the final speed of 1547MHz. He also managed to take the effective RAM speed all the way up to 7336MHz. Of course, he couldn't just achieve the clocks without running some benchmarks, so that's what he did. After a run of 3DMark 11, we saw some impressive results.
With the help of a 3960X running at 4.5GHz, TiN managed a whopping 20962 points. This is basically double the score of a stock clocked card. To match this score, one would need to use two AMD HD 7970s clocked at 1260/7400 MHz or two GTX 680s at 1527/7132. What an incredible card. It'll be interesting to see how the upcoming dual-Tahiti chip will perform in comparison.