for versus foreach : an easy and efficient way to improve .NET code performances

In a recent post, Patrick Smacchia shows how the "for" loop is more performant than the foreach one. In many cases the foreach loop simplify the comprehension of algorithms, mainly in complex algorithm. But in small methods or quite straight forward tasks, the use of the "for" can be a huge performance upgrade.

• for loops on List are a bit more than 2 times cheaper than foreach loops on List.
• Looping on array is around 2 times cheaper than looping on List.
• As a consequence, looping on array using for is 5 times cheaper than looping on List using foreach (which I believe, is what we all do).

the complete article is there :

http://codebetter.com/blogs/patricksmacchia/archive/2008/11/19/an-easy-and-efficient-way-to-improve-net-code-performances.aspx