Chrome 37 brings 64-bit support for Windows and now Chrome 38 brings 64-bit support for Mac OS. Chrome 37 is currently in beta and requires reinstalling the software in Windows, while Chrome 38 is available in the Dev and Canary channels, but it doesn't require reinstalling the browser in Mac OS. The Canary build runs alongside stable/beta/dev Chrome and it's updated daily.
In addition to better performance and fewer crashes, 64-bit Chrome for Mac also lets you use 64-bit plugins like Java. Until now, you had to use a different browser to load Java content. "Chrome does not support Java 7 on Mac OS X. Java 7 runs only on 64-bit browsers and Chrome is a 32-bit browser," informs Oracle's site.
Don't get too excited. Chrome will soon remove support for NPAPI plugins, so you'll still have to use Safari or Firefox to open pages that include Java applets.