Their public interfaces appear similar. The documentation states that the SemaphoreSlim is a lightweight alternative and doesn\'t use Windows Kernel semaphores. This resou
Regarding "short times" controversy:
At least SemaphoreSlim MSDN documentation states that
The SemaphoreSlim class is the recommended semaphore for synchronization within a single app.
in Remarks section. Same section also tells the main difference between Semaphore and SemaphoreSlim:
The SemaphoreSlim is a lightweight alternative to the Semaphore class that doesn't use Windows kernel semaphores. Unlike the Semaphore class, the SemaphoreSlim class doesn’t support named system semaphores. You can use it as a local semaphore only.