Google upgraded the beta version (4.0.223.16) of its Chrome browser yesterday, boasting a 30% speed improvement over the current production edition and adding integrated bookmark synchronization. Developers Idan Avraham and Anton Muhin, who announced the release, tout Chrome 4.0's faster JavaScript rendering speeds. 'We've improved performance scores on Google Chrome by 30% since our current stable release, and by 400% since our first stable release,' they said, referring to Chrome 3.0. The new beta includes the ability to sync bookmarked sites across multiple computers