64-bit vs 32-bit

[Abdullah Ramazanoglu]

Daniel Axtell dedi ki:

> I'm building a 64-bit sempron desktop system for a novice user who's used
> to Windows.  I know it's possible to set up a chroot environment to run
> 32-bit plugins for the browser, but for a non-sophisticated user that
> seems like it would be hard to maintain updates, etc.
>  
>  Will there be much of a performance hit if I run 32-bit Kubuntu on a
>  64-bit machine?  It seems like a simpler way of handling the plugin
>  problem.

Amd64 architecture has more instructions, double the number of registers,
and larger register width (not just for addressing, but also for data
handling). So, even the most lame application which doesn't need 64-bit
addressing, doesn't use 64-bit data, and doesn't stand a chance to make use
of the extended instructions, will still benefit from double the number of
registers.

There are many benchmarks on the Net comparing 32-bit vs 64-bit compiled
apps on amd64 (last checked more than a year ago, though). On overall
average there seems to be around 35% performance difference between 32 and
64 bit compilations. And this is for i686 vs amd64 target architectures.
With Kubuntu (Debian) the diff ought to be even more, as we're comparing
i386 vs. amd64 compilations here.

As for the 32-bit plugins, "nspluginwrapper" does quite a good job there. It
facilitates using 32 bit plugins (confirmed flash and realplayer) under
native 64-bit FF and Konq, without chroot. There are still a few apps
unavailable for 64-bit, though, like wmv9 support (w32codecs).

-- 
Abdullah Ramazanoglu
aramazan ÄT myrealbox D0T cöm