(For those curious but not curious enough to read the article, it's a 30% improvement in the V8 and Sunspider javascript benchmark scores.)
Also: windows only, no OS X or Linux binary for this beta. Sigh. I want to think they're serious about being cross platform, but stuff like this tells me that "everyone" in the developer group is on windows and the other platforms are still just sometimes-updated ports.
Wow. I'm guessing this is because Google really wants this on Win PCs, not because the developers are such VS fans.
But the point was more architectural: clearly Chrome is a windows program. With a little porting work, you can make it run elsewhere. So that's the development model they've picked. Do the work on windows, then hand it off. There's no simultaneous work going on, and features travel in only one direction. If a windows developer commits something that breaks Linux or OS X, it's "someone else's" problem to fix during porting.
Contrast this to Firefox, for example, where (the occasional glitch notwithstanding) the assumption is that every build works on every platform. People on Linux care about regressions on windows, etc... The model is that the software is portable first, and not "a port".
http://www.chromeexperiments.com/detail/balldroppings/
Run it on the current stable Chrome, then try the new beta.