title: What about using LINQ or Yield Return in for loops?
body: <p>Currently I'm working on a 2D XNA game. It needs optimizing, because the multiplayer mode is not performing well. In code we have mostly used foreach loops, and have not used LINQ or yield return statements anywhere. I understand we can win some performance here. Since for loops are faster, I was thinking of replacing all foreach loops.</p>
  
  <p><strong>But, however, I can't benefit from the yield return statement in a for loop, can I?<br>
  Also, will LINQ still be useful when iterating using a for loop?</strong></p>
  
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  <p>For example, I have a list of 1000+ shapes (squares, triangles, circles...), and I want to enumerate through all squares (75%) at a certain position. What's the best way of doing this?<br>
  What should I use? Arrays, lists, for loops, foreach loops, yield return and/or LINQ?</p>