Question

When I was reading this tutorial I noticed the following performance tip about using structs in C#:

Unless you need reference type
semantics, a class that is smaller
than 16 bytes may be more efficiently
handled by the system as a struct.

I looked for similar question in stackoverflow and I found some questions that talk about performance best practices in ADO.Net, Networking, Streams, but not about performance best practices in C# (The language).

I want to add another tip about using the integer types:

The runtime optimizes the performance
of 32-bit integer types (Int32 and
UInt32), so use those types for
counters and other frequently accessed
integral variables.

Answer 1

1. Strings are Immutable.
2. Understand the using statement.
3. Understand Boxing and how Generics help.
4. Understand how the Garbage Collector works.
5. Parallel programming in .Net 4.0
6. Understand how File IO affects performance.

Eric Lippert talks alot about optimization. I would read his blog.
I would check out Jon Skeet’s blog also.