[R] Use of processor by R 32bit on a 64bit machine

Uwe Ligges ligges at statistik.tu-dortmund.de
Tue Jun 29 15:34:32 CEST 2010

On 29.06.2010 15:30, Joris Meys wrote:
> Dear all,
> I've recently purchased a new 64bit system with an intel i7 quadcore
> processor. As I understood (maybe wrongly) that to date the 32bit
> version of R is more stable than the 64bit, I installed the 32bit
> version and am happily using it ever since. Now I'm running a whole
> lot of models, which goes smoothly, and I thought out of curiosity to
> check how much processor I'm using. I would have thought I used 25%
> (being one core), as on my old dual core R uses 50% of the total
> processor capacity. Funny, it turns out that R is currently using only
> 12-13% of my cpu, which is about half of what I expected.

An Intel Core i7 Quadcore has 8 virtual cores since it supports 
hyperthreading. R uses one of these virtual cores. Note that 2 virtual 
cores won't be twice as fast since they are running on the same physical 
core. Hence this is expected.

Uwe Ligges

> Did I miss something somewhere? Should I change some settings? I'm
> running on a Windows 7 enterprise. I looked around already, but I have
> the feeling I overlooked something.
> Cheers
> Joris
> sessionInfo()
> R version 2.10.1 (2009-12-14)
> i386-pc-mingw32
> locale:
> [1] LC_COLLATE=English_United States.1252  LC_CTYPE=English_United
> States.1252    LC_MONETARY=English_United States.1252
> [4] LC_NUMERIC=C                           LC_TIME=English_United
> States.1252
> attached base packages:
> [1] grDevices datasets  splines   graphics  stats     tcltk     utils
>     methods   base
> other attached packages:
> [1] svSocket_0.9-48 TinnR_1.0.3     R2HTML_2.0.0    Hmisc_3.7-0
> survival_2.35-7
> loaded via a namespace (and not attached):
> [1] cluster_1.12.3 grid_2.10.1    lattice_0.18-3 svMisc_0.9-57  tools_2.10.1

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