And, according to Google, it’s twice as stable, with half as many crashes as the 32-bit version on normal web pages. Still not convinced? 64-bit Chrome is also faster on various web benchmarks. For example, a comment in this bug report notes that the 64-bit version of Chrome provides additional protection from third-party software–like antivirus programs that shouldn’t be touching the browser–hooking into Chrome’s sandboxed processes. The 32-bit version of Chrome can’t use the same technique.
There are other ways Chrome behaves more securely on 64-bit versions of Windows, too, but Google doesn’t have a slick page explaining all of them. Google has worked with Adobe to improve Flash’s protections against various type of attack, and these exploit mitigations are more effective on 64-bit versions of Chrome. In addition, the 64-bit version of Chrome includes a 64-bit version of Adobe Flash.