Not that I know.
Two remarks:
- The advantage for Javascript execution, at least, is non-existing or 32 bit is faster: http://img17.imageshack.us/img17/3673/69795024.png.
- http://izanbardprince.wordpress.com/2009/05/12/do-64-bit-web-browsers-perform-faster-than-32-bit-browsers/ discusses the disadvantages of 64-bit browsers
I don't think the time is ripe yet.
Kees
Are there any 64bit browsers, other than IE8? Thanks!

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