We were able to benchmark Intel's first Atom powered smartphone using Benchmark PI. As you can see from the picture below it scores 743ms in Pi.  The HTC Thunderbolt (Snapdragon 1GHz) clocks in at 888ms, and the LG Optimus 2X (Tegra 2) clocks at 550ms. Of course, lower scores are better.

It looks like the phone is still slower than Tegra 2 devices, although Lenovo states that before the phone is released the OS will be more refined, so we could see better performance once it hits shelves.