Expreview has yet another exclusive, the site compares the upcoming 45nm Core 2 Duo E8400 processor with the 65nm Core 2 Duo E6850. Both processors are clocked at 3GHz so this review gives us an idea of the improvements in Intel's 45nm process and the new Wolfdale architecture.
The site reports the processor could easily be overclocked to 4.05GHz (450MHz FSB) on air. Also impressive are the temperatures: in idle the 45nm Wolfdale runs 8°C less hot than the 65nm Conroe and in load the difference is 13°C! The E6850 runs at 46°C while the new 45nm E8400 remains at a cool 33°C. Even when overclocking the chip to 3.6GHz it stays relatively cool.
The reviewer also compared the power consumption of both processors. Unfortunately there's no difference in idle but in load the 45nm Wolfdale uses almost 20W less.
Performance-wise there's not a lot of difference but the thermal and power efficiency improvements are pretty impresive. Check it out over here.