updated 03:50 pm EST, Tue December 7, 2010
The boosts were attained thanks to adaptive compilation. Benchmarks that take a few milliseconds to execute, such as SunSpider, don't benefit as much with Crankshaft due to their small size. Crankshaft heavily optimizes code that's frequently used and does not concern itself with optimizing code that isn't. The more work an app does the bigger the gains will be, Google said.
A V8 engine with Crankshaft for Intel's 32-bit processor architecture is now available and should be in developer versions of Chrome. The ARM and 64-bit versions are currently under development.