Do Not Assume Problems Arises Only From Business Logic

When beginning to diagnose performance problems, we often assume the problem is in our business logic. Don’t forget that the areas of our code that provide infrastructure can cause problems as well. Areas such as HttpHandlers, HtmlHelpers, mapping, logging, or IoC frameworks are increasingly at the root of performance problems. While business logic still causes its share of problems, infrastructure code is quickly gaining in the performance problem race.

50 Ways to Avoid Find and Fix ASP.NET Performance Issues