what are the benefits of 64-bit vs 32bit?
64 is faster because components of the CPU (and no, I am not taking about ram quantity management) are not used when using 32bit compatibility mode on a modern (older than 2005) CPU.
the performance increase varies from nothing to 400% faster (that is actual benchmarked performance not hypothetical performance. The 400% figure came from some tests with very specific software done by xbitlabs).
although most programs will get closer to 30-50% improvement. I personally benchmarked 7zip to work 27% faster in 64bit mode.
Specifically for browsers. IE is much faster in 64bit and Firefox is several times faster in 64bit mode. this is particularly noticable when you are using "restore tabs" option with many open tabs (opening 100 tabs at once on load can take a while).
If you want to know the benefits of chrome 64bit. well, hypothetically it would be faster for the same reason other browsers are. But I haven't tested it yet since i was waiting for it to get to stable (no point in speed if you are crashing).
EDIT: I went ahead and tested with my crummy ancient work laptop. It is massively faster and more responsive.
EDIT2: here is goggles spiel
http://blog.chromium.org/2014/06/try-out-new-64-bit-windows-canary-and.html
Speed: 64-bit allows us 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: 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 us better defend against exploitation techniques such as JIT spraying, and improve the effectiveness of our existing security defense features like heap partitioning.
Stability: Finally, we’ve 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.
not mentioned there is that 64bit chrome can use 64bit VP9 video decoder in youtube and that is also 15% faster.
EDIT3: Turns out it added (and I didn't notice) a "let chrome run in background" option. it starts up / closes a lot slower without that. but still significantly faster than it was before