AnandTech took a quick look at Intel's new 45nm mobile Penryn processors:
The new Core 2 Duo T9000 and T8000 series work in modified Santa Rosa platforms, using the same mobile 965 chipset. As long as there is motherboard support, you can use a mobile Penryn (similar to the situation on the desktop).
There should be an obvious performance increase from these new mobile Penryn chips, but the more interesting impact should be on battery life. Mobile Penryn offers two technologies that don’t exist on the desktop chips, one of which is targeted specifically at increasing battery life.
Mobile Penryn supports a deeper sleep state when a core is idle, allowing the chip to go into a near-reset state with only the absolute minimal circuitry powered. The other mobile-specific feature is Intel’s Dynamic Acceleration Technology, which we will discuss and test later in today’s article.
Check it out over here. The site tested the battery life of a 2.6GHz Merom and 2.6GHz Penryn processors and concludes it went up by 5-15%, depending on the application you're using. During DVD playback they got a 7% battery life increase and in office productivity even up to 16.5% more. Besides bettery power efficiency the new chips also offer more performance, 6.8% in the single-core tests and 9.1% in multithreaded benchmarks.