The Thread.SpinWait(int) method is useful for implementing locks. Classes in the .NET Framework, such as System.Threading.Monitor and System.Threading.ReaderWriterLock, use this method internally. Thread.SpinWait(int) essentially puts the processor into a very tight loop, with the loop count specified by the iterations parameter. The duration of the wait therefore depends on the speed of the processor.

Contrast this with the Thread.Sleep(int) method. A thread that calls Thread.Sleep(int) yields the rest of its current slice of processor time, even if the specified interval is zero. Specifying a non-zero interval for Thread.Sleep(int) removes the thread from consideration by the thread scheduler until the time interval has elapsed.

Thread.SpinWait(int) is not generally useful for ordinary applications. In most cases, you should use the synchronization classes provided by the .NET Framework; for example, call Monitor.Enter(object) or a statement that wraps Monitor.Enter(object) (lock in C# or SyncLock in Visual Basic).