Once upon a time I was working at a different company, and we had a real-time process that generated statistics.
We had 2 classes of hardware, one windows based, and one Dec Unix based.
The Windows based systems (NT) had support for threads, so we used a back end program to watch the socket for messages, collect the messages, and periodically push the messages to the Informix db, in 2 threads.
The Dec Unix system didn't support threads, so we used multi-processes with IPC. I think it was 3.

They both did the same thing, but we worked within the limitations of what we had at the time.

I guess the point is that both approaches worked, and were relatively efficient. But for my part, the multi process approach was much easier to work with and figure out what was happening when something went wrong. The multi thread approach took me longer to get working well. But that might have been because it was on Windows. I haven't done any multithreading on any other platform.