[R] Dismal R performance of Athlon moble CPU?

[Prof Brian Ripley]

On Wed, 23 Jul 2003, Jason Liao wrote:

> I have been using a laptop computer of Pentium III 1.13 Ghz. I heard
> that AMD's Athlon has excellent floating point capacity. So I bought a
> Athlon 2200+ laptop yesterday. I expected that new Athlon 2200+ will be
> twice as fast as the P III 1.13 GB. I ran a R simulation program and
> the new computer is only 30% faster, in fact slightly slower than a
> Celeron 1.50 GB laptop. I am very disappointed by this. What is your
> experience with Athlon? Should I stick to Intel in the future? Thanks.

So I expect you think a P4M 1.4GHz (on which I am writing this) should be
a lot faster than a PIII 1GHz?  It is often slower.  Don't compare laptop
chips with desktop ones, nor different chip families (an Athlon 2200 is
not 2.2GHz, BTW).  PIIIs seem the fastest per GHz, but they don't do many
GHz.

I am rather pleased with my dual Athlon 2600, but then P4's don't allow 
multiprocessors and the machine with dual Athlons was cheaper than a 
comparable one with a single 2.4GHz P4.

You have tuned an ATLAS implementation to your CPU, I take it?  If not, 
that's the first step to optimal R performance.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595