But it showed that 4Ghz on air is possible with Yorkfield. You don't need fancy heatsinks. You don't need exotic water coolings. Just an aftermarket air cooling, like Turniq Tower, and you can OC that chip to 4Ghz.
I heard from my bud at Intel that they have used the Skull Trail system you saw at IDF to hit 4.5GHz on liquid cooling using Harpertown processors. I don't know if that is true, he does like to brag so please take with a grain of salt.