Fudo mentioned that Thuban will have a "C-state performance boost". This could either be an overclocking based on core utilization like described in a somewhat older patent or already be a hardware based overclocking reusing a remainding thermal budget left by cores running at lower p states, not necessarily being switched off.
The latter variant is described here: http://www.freepatentsonline.com/20090235108.pdf
. This doesn't require power gating, which will be presented on ISSCC '10 (this is just a power saving measure). And it has nothing to do with the more advanced power management features of BD (CC6 state, APM boost...).
Let's look at the numbers given in the linked document to get a clue, how it might work in Thuban:
The doc describes a dual core CPU and it's power states. Figures 5A and 5B show a transition to an overclocked state (P Max) for one core. In this example the boost would be 300 MHz over the standard clock of 2.6 GHz. The core clocks for Istanbul are similar and the per core TDP might be too (15 W, resulting in 90 W TDP - not ACP - for the cores alone). So we might see a Thuban boosting heavily utilized cores by maybe 200 to 400 MHz if the other cores are less utilized. This would make a lot of sense for a six core desktop CPU running desktop apps or games.