Andrew Halliwell <spike1@ponder.sky.com> writes:

> Aragorn <aragorn@chatfactory.invalid> wrote:
>>> Are there any advantages and disadvantages between 686 and amd64 beside
>>> being able to use more memory which I doubt I am going to (2 GB is
>>> enough).
>>
>> Well, the /AMD64/ kernels are more likely to contain some processor-specific
>> code optimizations than a generic /i686/ kernel,
>
> There's a bit more to it than that....
> x86-64 is more than just a wider address bus, it also contains a shedload
> more cpu instructions, such as SSE3, iirc. There're also a lot more
> registers available in 64bit mode. Which means less fetching from RAM during
> calculations.
>
> These enhancements may (in some situations) make it faster...
> But I think the general consensus is, speed is generally slightly slower
> because 64 bit applications tend to be slightly bigger due to the extended
> instruction set and data-width taking more memory/disk space.

This was hotly contested by some in comp.os.linux.advocacy but is
effectively correct. I saw no speed improvement in 64 bit over 32 bit
and just suffered from a far less stable system.

>
> If you don't need more than 4gig of RAM, chances are, you're fine in 32 bit
> mode, and may even be slightly better off, performance wise.

And certain things like flash do not work properly.

See:

http://groups.google.com/group/comp....5d987c45c9499c

It is however getting better.

--
<wolfgang> the problem with the 'go find a real girl' admonition is
that so few of them actually have naked transformation
sequences
<reality> Dude, my girlfriend changes like four times a day