The performance of any system is considered as a key part of the requirements that client usually ask for implicitly. The poor perform application is most likely going to be failed because of that even if it is doing lot of very cool functionalities.
Recently I read an interesting article about this topic published on CodeGuru. They highlighted couple of key actions that is easy to be implemented and they are almost effortless but at the end those actions will improve the overall performance of you application by better utilization of server CPUs.
They depending on the fact that the CPUs we have these days is much sophisticated that previous days and we need to take benefits of that. I strongly recommend reading this article