I'm a total newbie, but I was writing a little program that worked on strings in C# and I noticed that if I did a few things differently, the code executed significantly faster.
So it had me wondering, how do you go about clocking your code's execution speed? Are there any (free)utilities? Do you go about it the old-fashioned way with a System.Timer and do it yourself?
What you are describing is known as performance profiling. There are many programs you can get to do this such as Jetbrains profiler or Ants profiler, although most will slow down your application whilst in the process of measuring its performance.
To hand-roll your own performance profiling, you can use System.Diagnostics.Stopwatch and a simple Console.WriteLine, like you described.
Also keep in mind that the C# JIT compiler optimizes code depending on the type and frequency it is called, so play around with loops of differing sizes and methods such as recursive calls to get a feel of what works best.