As soon as Ramm or anyone else gets his chip,we'll know how it OCs on air and performs .Some amount of chips will be available before the official launch.
As for hiding comment,they are not hiding anything,but like Jazzman said,they are keeping the folks interested by leaking bit by bit during longer period of time.It would wear off if they had shown it all 1 month prior to release. As all can see from Chicago event,the chips are very tolerant to volts and run cool.2 or 3 more events like this one are scheduled until the launch so it will be interesting to see what others will say.