Overclocking is dangerous. Today's GPUs are beasts that produce a lot of heat, that have different parts clocked differently at a given moment, and those clocks are dynamically changing all the time. To mess with that and keep stability of the whole thing requires a very, very careful implementation. The Nvidia devs decided it would take too much time to tackle this challenge, so they decided to simply not tackle it.
No announcement yet.
Nouveau Lights Up The GK106 Kepler