C# - Number Of Cores and Processors

If your working with threads in c# is can be useful to be able to find out the number of processors and the total number of cores avilable to an application so that you can adjust the maximum number of threads to a sensible value when an application starts. After all there is no point in attempting to execute 100 high processor intensive task's in a system with only 2 cores. It will just grind your application and possibly windows to a complete halt.