title: select on nvarchar(max) column really slow
body: <p>SQL Server 2008 R2. I'm doing a select on a table with ~70,000 rows.
  If I try to query an nvarchar(max) column, where the longest string is 2,433 characters, it takes 66 seconds. </p>
  
  <pre><code>select Comment from StudentAssessmentComments
  </code></pre>
  
  <p>Filtering by an indexed column to 17,000 rows still takes ~17 seconds.</p>
  
  <pre><code>select Comment from StudentAssessmentComments where FileYear = 2016
  </code></pre>
  
  <p>If I query a different, unindexed column, its immediate (&lt; 1sec).</p>
  
  <pre><code>select StaffID from StudentAssessmentComments
  </code></pre>
  
  <p>Is it normal for an nvarchar(max) column to perform so badly? If not, does anyone have any suggestions? Thanks for any help.</p>