On Tue, 2008-06-17 at 12:17 +0100, Daniel Barlow wrote:
> Peter-Henry Mander <oxlug@???> writes:
>
> > Until everyone has oodles of physical RAM, and I mean 128 to 1024
> > gigabytes, there's no big advantage in using 64 bits.
>
> My hazy recollection says that the situation is not quite as clear-cut
> in the specific case of x86-64, because when you go to long mode you
> additionally get (a) twice as many registers, (b) an ABI that uses the
> SSE instructions for floating point instead of the weird x87
> stack-based thing. I would not be surprised if either or both of
> these (more likely the former) made a significant difference on some codes.
> It certainly makes code _generation_ easier ...
The downside being the wider chunks of memory taking longer to pass
around
For desktop use, it balances out to no significant speed gap. For some
apps (e.g. media encoding) then it can be MUCH faster on amd64 than i386
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/ Jo Shields <jms@???> \
| Systems Manager, |
\ Oxford Supercomputing Centre /
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