[R] Snow & rvpm

[vittorio]

At office, using the internal LAN at my disposal,  I'm having a go at parallel 
computing - to begin with - with pvm, rpvm & snow.
The two boxes are as follows

Remote machine uffbsd:
CPU: Intel(R) Pentium(R) 4 CPU 2.00GHz (1994.13-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf24  Stepping = 4
 real memory  = 260046848 (248 MB)

This machine NbBSD:
CPU: Mobile Intel(R) Pentium(R) 4 - M CPU 2.00GHz (1993.54-MHz 686-class CPU)
real memory  = 536674304 (511 MB)

And starting library snow under R I have the following situation

clusterCall(cl, function() Sys.info()[c("sysname", 
"release","nodename","machine")])
[[1]]
      sysname       release      nodename       machine
    "FreeBSD" "5.4-RELEASE" "uffbsd.myd"        "i386"

[[2]]
         sysname          release         nodename          machine
       "FreeBSD"    "6.0-RELEASE" "NbBSD.myd"           "i386"

NOW,
using the example of boot in the end of page 
http://www.stat.uiowa.edu/~luke/R/cluster/cluster.html

I find this amazing result:

> system.time(cl.nuke.boot<- 
clusterCall(cl,boot,nuke.data,nuke.fun,R=999,m=1,fit.pred=new.fit,x.pred=new.data))
[1]  0.0078125  0.0078125 27.9609375  0.0000000  0.0000000
>  system.time(nuke.boot<- 
boot(nuke.data,nuke.fun,R=999,m=1,fit.pred=new.fit,x.pred=new.data))
[1] 26.976562  0.109375 28.484375  0.000000  0.000000
> 
There's not that much gain in time between my cluster and the local 
computation, isn't it.
Now my question is:
What could have been gone wrong and what should I verify?

Ciao
Vittorio