Intel revealed more details about Santa Rosa today, including changes to draft 802.11n support and a significant change to the CPU. Core 2 is getting yet another revision, this one promising to boost performance even further in single-threaded applications. While they aren't calling it “overclocking”, the new technology will allow one core on the CPU to increase its clock speed after putting the other core to sleep, supplying extra power to the single core as needed. Of course, it is overclocking – above the default frequency – but is within the chips normal operating specifications and has even been given a fancy name:

This is called Enhanced Dynamic Acceleration Technology. We've had problems implementing it, but we've been able to do it in Santa Rosa," Eden said.
This new Core 2 Duo will bring the best of both worlds, a chip that can execute multiple threads at a time via having multiple cores at its disposal, but also optimize itself for single threads when it is advantageous. The new CPU, along with the new Santa Rosa platform it is destined for, is still geared for a release in the second half of this year. I am definitely interested in finding just how far the chips will push themselves and what sort of performance boosts they can offer.