Worth noting that having number of IOCP worker threads == number of cores has always been the official suggestion for building IOCP applications. Eg https://do

Worth noting that having number of IOCP worker threads == number of cores has always been the official suggestion for building IOCP applications. Eg https://docs.microsoft.com/en-us/windows/win32/fileio/i-o-completion-ports https://docs.microsoft.com/en-us/windows/win32/fileio/i-o-co... >The concurrency value of a completion port is specified when it is created with CreateIoCompletionPort via the NumberOfConcurrentThreads parameter. This value limits the number of runnable threads associated with the completion port. >[...] >The best overall maximum value to pick for the concurrency value is the number of CPUs on the computer.