title: Why is R slower on my (stronger) Desktop than on my (weaker) laptop?
body: <p>I'm using a Dell Latitude E7440 <strong>Laptop</strong> with Windows 7 Enterprise OS, <strong>8GB RAM</strong>, 64-bit OS, Intel(R) Core(TM) i7-4600U CPU @ 2.10GHz Processor, 2701 Mhz, 2 Cores, 4 Logical Processors (that's 4 cores).</p>
  
  <p>I'm using a Dell Precision Tower 7810 <strong>Desktop</strong> with Windows 7 Enterprise OS, <strong>32GB RAM</strong>, 64-bit OS, Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz <strong>2</strong> Processors, 2401 Mhz, 6 Cores, 12 Logical Processors (that's 24 cores).</p>
  
  <p>A good demonstration of my use of R would be running binary classification using <code>gbm</code> in RStudio on 100K-sized data with ~300 features. But whatever I do on my laptop R version (all other software closed, no use of parallelization), is considerably <em>faster</em> than on my Desktop R version. How can that be? What do I need to do to find out?</p>
  
  <p>Laptop:</p>
  
  <pre><code>&gt; sum &lt;- 0; system.time(for (i in 1:1000000) sum &lt;- sum + i)
     user  system elapsed 
     0.36    0.00    0.36 
  &gt; memory.limit()
  [1] 8097
  &gt; sessionInfo()
  R version 3.3.1 (2016-06-21)
  Platform: x86_64-w64-mingw32/x64 (64-bit)
  Running under: Windows 7 x64 (build 7601) Service Pack 1
  
  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] stats     graphics  grDevices utils     datasets  methods   base     
  
  loaded via a namespace (and not attached):
  [1] tools_3.3.1
  </code></pre>
  
  <p>Desktop:</p>
  
  <pre><code>&gt; sum &lt;- 0; system.time(for (i in 1:1000000) sum &lt;- sum + i)
     user  system elapsed 
     0.52    0.00    0.52 
  &gt; memory.limit()
  [1] 32684
  &gt; sessionInfo()
  R version 3.3.1 (2016-06-21)
  Platform: x86_64-w64-mingw32/x64 (64-bit)
  Running under: Windows 7 x64 (build 7601) Service Pack 1
  
  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] stats     graphics  grDevices utils     datasets  methods   base     
  
  loaded via a namespace (and not attached):
  [1] tools_3.3.1
  </code></pre>