title: StringBuilder Append vs AppendFormat efficiency in C#
body: <p>Which is more efficient in C#, 1 or 2?  </p>
  
  <pre><code>StringBuilder sb = new StringBuilder();
  sb.Append("my string " + myVar + " my string");     // 1
  sb.AppendFormat("my string {0} my string", myVar);  // 2
  </code></pre>
  
  <p>I'm guessing that the question could also be rephrased:  </p>
  
  <pre><code>string y = "my string " + myVar + " my string";              // 1
  string x = String.Format("my string {0} my string", myVar);  // 2
  </code></pre>