In most cases 64-bit applications always outperform 32-bit. And I think that’s the reason Google has built and launched 64-bit version of Chrome. As expected, the 64-bit version of Chrome promises to offer 25 percent increase in performance, more security and crash rates reduced to almost half. If you are running 64-bit version of Windows 7 or Windows 8/8.1, it is highly recommended to try out the Dev and Canary channels of 64-bit chrome. This version takes full advantage of the 64-bit operating system capabilities and 64-bit capable processor.
Speed: 25 percent improvement in performance
64-bit allows to take advantage of the latest processor and compiler optimizations, a more modern instruction set, and a calling convention that allows more function parameters to be passed quickly by registers. As a result, speed is improved, especially in graphics and multimedia content, where we see an average 25% improvement in performance
Security: Better defense against exploitations
With Chrome able to take advantage of the latest OS features such as High Entropy ASLR on Windows 8, security is improved on 64-bit platforms as well. Those extra bits also help better defend against exploitation techniques such as JIT spraying, and improve the effectiveness of existing security defense features like heap partitioning.
Stability: Crash rates are almost half that of 32-bit
Google has observed a marked increase in stability for 64-bit Chrome over 32-bit Chrome. In particular, crash rates for the the renderer process (i.e. web content process) are almost half that of 32-bit Chrome.