title: Pandas performance varies between mac and linux
body: <p>I have a simple function.</p>
  
  <p>The dataframe has <code>1713078</code> rows.The following simple function: </p>
  
  <pre><code>self.df = self.df[~self.df['RR'].str.contains(":c", na=False)]
  self.df.fillna('', inplace=True)
  </code></pre>
  
  <p>takes <code>2x</code> time on centos6.4 via jenkins with 16 gb ram and 16 CPU's , when compared to mac 16 gb ram etc.I am not sure what can be the culprit here.
  Can it be due to <code>jenkins</code>?as rest all is same.I am not even sure what more details can i give here.</p>