Google has unveiled Chrome 39 FINAL for Windows, Mac and Linux. The big news with version 39 is the long-awaited arrival of a native 64-bit build for Mac users. Unlike the Windows version, which offers both 32-bit and 64-bit builds, the Mac build is now 64-bit only, and existing users with supported Macs will be automatically upgraded to the new version.
There are a number of good reasons for switching to 64-bit, all of which Google announced when it unveiled the first 64-bit Mac beta. These include faster performance thanks to a "superior" instruction set, enhanced security and -- thanks to the way Chrome no longer requires 32-bit system libraries -- quicker start times and reduced memory usage.
The switch to 64-bit means that Chrome will no longer be updated on Macs built with the first generation of Intel chips, which first launched in January 2006 and were 32-bit.