1.1.4 slow to respond

I am getting slow response time from the server for authentication requests (chap/mschap) that eventually fail (users submitting wrong password). The problem is that the NAS is sending about 3 requests before getting a response. By the time the deny arrives, it is out of order and the NAS logs an unexpected packet (though it correctly denies the user). I am wondering if disabling all authentication/authorization methods except chap/mschap would solve this by speeding the response time. The server is not the speediest machine... 1 GHZ processor/1GB ram, but is dedicated for freeradius except for serving some static web pages. I have never seen system usage stats above nominal levels. Regards, Andrew