Load Balancing Issue

Hi, I am using Freeradius 2.2.0 on redhat 5. My goal was to increase the speed of user authentication. To achieve this I configured Load Balancing (with realms). I have a proxy Freeradius server, that is just proxying requests to 2 other freeradius servers. Problem is that, when i sent a specific number (10 million) requests to proxy server (that just proxy requests to 2 other servers) , it took about 45 minutes to complete these requests. But if I send same amount of requests direct to on of the server (without sending it to proxy server), requests are entertained rapidly (in around 16 minutes). Can any one please tell me , what's the issue. Thanks a lot.