Source: Engadget
The new version was announced on the Chromium blog, along with a list of benefits that the switch to 64-bit brings to the table. Thanks to compiler optimizations and a more advanced instruction set, Google says it is getting big speed boosts. In graphics and multimedia content, the 64-bit version of Chrome is averaging a 25 percent improvement in performance. Security is better, too, thanks to high-entropy address space layout randomization in Windows 8, making memory hacks harder. Google also notes that it has seen "a marked increase in stability for 64-bit Chrome over 32-bit Chrome," particularly in the render process, which crashes half as much on 64-bit builds.
For now, the 64-bit version of Chrome is only available on Windows 7 and 8, and only in the developer and canary (nightly) channels. These are unstable builds that aren't meant to be used by novice users, but anyone looking to try out the cutting edge of Chrome development can try the dev version here or canary here...
Source: Ars Technica