[R] Optimal platform for R

[Prof Brian Ripley]

On Thu, 9 Mar 2006, gwelleni at bidmc.harvard.edu wrote:

> I'm looking to buy a new desktop which will primarily be used for
> analyses of large datasets (100s of MB). I've seen postings from several
> years back re the 'optimal' platform for running R, but nothing more
> recently.

It is a subject which comes up every few months.  Many of the developers 
are running dual (or dual-core) Opterons/Athlon 64s under Linux these 
days.

> Specifically, I want to know: 1) if I run R under Windows, does having a
> dual-processor machine help speed things up? And 2) is it still true
> that R performs about as well under Windows as Linux?

Duncan Murdoch has already mentioned the 64-bit advantage if you need 
large datasets, but there is also a speed penalty if you do not.  Your 
description seems on the margins (depends how many 100s and what the 
format is and what you want to do).  One advantage of AMD64 Linux is that 
I can run either 32- or 64-bit versions of R and choose to have speed or 
space for any given task.

A dual processor will be of little help in running R faster.  R's 
interpreter is single-threaded, and although you can get some advantage in 
using multi-threaded BLAS libraries in large matrix computations these are 
not readily available for R under Windows, and the advantage is often 
small under Linux. Running two or more instances of R will take advantage 
of dual processers, and I have been running dual CPU machines for a 
decade.

As for Windows vs Linux, R runs on the same hardware at about the same 
speed when comparing the standard Windows build with a shared library 
version on Linux (standard for e.g. the RH RPMs), but the standard Linux 
build is 10-20% faster. For one set of comparisons see

 	http://sekhon.berkeley.edu/macosx/

-- 
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