Mailinglist Archive: opensuse (4656 mails)

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Re: [opensuse] Have 4G, any reason to use x86_64 over i386?
  • From: John Andersen <jsa@xxxxxxxxxxxxxx>
  • Date: Wed, 24 Jan 2007 20:20:50 -0900
  • Message-id: <200701242020.51135.jsa@xxxxxxxxxxxxxx>
On Wednesday 24 January 2007 14:44, Anders Johansson wrote:
> On Thursday 25 January 2007 00:33, Linda Walsh wrote:
> > 32-bit programs execute faster
> Have you actually tried this? In many cases it is true, but it is heavily
> dependent on the application, and how well it has been optimised for 64 bit.
> I would suggest that you do your own benchmarks with the applications you
> intend to use

Its also dependent on the processor. Core 2 Duo timeings are such that
the most frequently used 64bit instructions execute in the same number
of clocks as their 32bit version in spite of having to fetch twice the data
from memory. The memory fetches are also just as fast as long as
the processor correctly predicted any branching.
I don't know about the AMD 64bit processors.

John Andersen
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