questions about 3.0.7 under load using file listen server

We are running 3.0.7 and writing packets to a file to be read by a detail server. We find that, when the server is under a lot of client load the detail server stops working. When the load reduces, the detail server resumes sending packets. Is this a deliberate design? We didn't see that with earlier versions. Perhaps there is some config we can adjust? Thanks in advance. Adrian