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Re: Re: Comparison of Mathematica on Various Computers


Hi, Joseph 

On Pr, 2006-02-13 at 03:15 -0500, Joseph Gwinn wrote:
> In article <dsmueo$da0$1 at smc.vnet.net>, albert <awnl at arcor.de> wrote:
> 
> > Renan wrote:
> > 
> > > On 2/10/06, fizzy <fizzycist at knology.net> wrote:
> > >> Can someone explain why AMD does so well on this test and Pentium does so
> > >> poorly by comparison??
> > >> I am planning to buy a new  computer and these tests seem to indicate
> > >> that a Mathematica user should buy an AMD machine.
> > > 
> > > I'd guess that an Athlon 64 CPU is faster than a Pentium 4
> > > (32-bit).(most AMD CPU's that I see in the benchmark are 64-bit)
> > 
> > hm, I hoped for good answers to that, but my guess is also that it is the
> > 64-bit vs. 32-bit which explain the difference to a big extent. Obviously
> > it will be less often necessary to use software arbitrary precision
> > arithmetic and when you have to it should be a big advantage to be able to
> > work with words of double size.
> > 
> > Maybe it would be worth to check whether there are "unfair" tests within the
> > benchmark like numerics with a precision which can be done in hardware on a
> > 64-bit processor but needs to be done in software on a 32-bit processor?
> > This is just another case where just a single number is not enough to
> > decide whether one or the other computer is faster for what you want to do
> > with it. So you should probably look into the results for specific parts of
> > the benchmark if that's possible...
> 
> Mathematica 5.x uses 64-bit floats for numerical evaluations.   It 
> doesn't matter if the quantity requires 64 bits or not.  Nor should it, 
> as Mathematica has no way to know such a thing.
> 
> If the platform does 64-bit arithmetic in hardware, so much the better.
> 
>  
> > > Does Mathematica support special instructions like SSE?
> 
> I'm guessing that it does not, because Mathematica is designed to be 
> portable to a wide range of computer platforms.
> 
When I installed (just for fun) Mathematica 5.1 on my old Texas laptop (Pentium
I, 75Mhz) and tried to run it I got "unknown instruction" message from
the kernel (if I correctly remember), not the frontend. 4.2 works fine
on that hardware. So there is a definetely some instructions used in the
Mathematica kernel 5.1 which are not supported by Pentium I chips. (If I
recollect correctly Mathematica 5.0 was also able to run on that hardware, but I
seldom used it, due to speed problems)


> Joe Gwinn
-- 
Arturas Acus <acus at itpa.lt>


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