I'm running Apache on a dedicated Windows 2008 server with a back-end process connected to Apache via FASTCGI. The back-end process is actually a game engine. Everything is working fine but I've noticed that things start to slow down when I have about 50 users hitting the server (which translates to about 25 HTTP requests per second). When I look at the Task Manager the CPU usage is between 1% and 5%.
So I'm looking for clues as to where to look to figure out why my response time is degrading even though the CPU doesn't seem to be anywhere close to maxed out.