performance issus, please help???

[Andy]

Are the Apache and Nginx servers separate physical servers or are they
VPS?

Have you checked if you're hitting network bottleneck? If each response
is 10KB, then 300 rps translate to 3MB/s, or 24mbps, add in all the
networking overhead and we're talking about 30mbps. Maybe you've hit the
bandwidth limit.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,214412,214449#msg-214449