title: count of unique values in a column, with speed as a consideration
body: <p>Is there a faster way to count unique values in a column?
  My second iteration of the formula uses a range for speed but receives a #NAME? error. Thanks.</p>
  
  <p>I have used the following formula to count the number of unique ip addresses in column 5.  --explained by Jeeped on msdn--</p>
  
  <pre><code>ActiveCell.Formula = "=sumproduct((ipsheet!C[5]&lt;&gt;"""")/ipsheet(ACAS!C[5],ipsheet!C[5]&amp;""""))"
  </code></pre>
  
  <p>the forumula works BUT it is really slow going over 5000+ entries. I have tried implementing the same formula as</p>
  
  <pre><code>With Sheets("ipsheet")                                                    'create range for ip addresses
       Set rngOfFindings = .Range(.Range("e1"), .Range("e1").End(xlDown))
  End With
  "=sumproduct((rngOfFindings&lt;&gt;"""")/countif(rngOfFindings,rngOfFindings&amp;""""))"
  </code></pre>
  
  <p>the result is #NAME? </p>