[R] Speed up R

[Prof Brian Ripley]

On Tue, 19 Jun 2007, Robert McFadden wrote:

> Dear R Users,
> I hope that there is someone who has an experience with a problem that I
> describe below and will help me.
> I must buy new desktop computer and I'm wondering which processor to choose
> if my only aim is to speed up R. I would like to reduce a simulation time -
> sometimes it takes days. I consider buying one of them (I'm working under
> Win XP 32 bit):
> 1. Intel Core2 Duo E6700 2.67 GHz
> 2. Dual-Core Intel Xeon processor 3070 - 2,66 GHz
> 3. AMD Athlon 64 X2 6000+
> Or simple Pentium 4?
>
> I'm very confused because I'm not sure whether R takes advantage dual-core
> or not.

Not under Windows XP.

The experience under Linux shows that on the right problem dual processors 
can help a lot (say 1.8x), but the gains are typically modest and can even 
be negative.

The advantage of dual processors is that you can use the machine for 
several things at once, including multiple R jobs.  For example, when I am 
doing package checking I am typically checking 4 packages at once on a 
dual processor machine to get continuous high utilization.

> If not, probably Athlon would be better, wouldn't be?

I have little doubt that a Pentium 4 would be much slower than the others.

I've just bought an Intel Core 2 Duo E6600 primarily to run 64-bit Linux, 
but it also has Vista 64 and XP (32-bit) on it.  I don't think the
differences between the current dual-core chips are really enough to
worry about: they will all look slow in less than a year.

-- 
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