Primate Labs has published initial benchmarks for the new MacBook and MacBook Pro using 8 test machines and Geekbench 2. They conclude that "Somewhat suprisingly, processor performance is virtually unchanged in the new MacBooks and MacBook Pros; the new NVIDIA chipset and the faster DDR3 memory havent managed to help increase processor performance."
The most notable improvement is in the graphics of course... "While the NVIDIA chipsets might not be as good as the Intel chipsets when it comes to processor performance, they far surpass Intel when it comes to graphics performance. This increased graphics performance is a huge gain for the MacBook"
Read More [via MacRumors]