nginx high load average

hello

i have server running as shared server Intel(R) Xeon(R) CPU E3-1225 V2 @ 3.20GHz 4 core and 16 g.b ram running onCentOS release 5.9 (Final) upload and download via php scripts like rapidshare

the problem is i have high connections on this server and i want to know how could i configure the nginx correctly

here is my current nginx.conf


user nobody;
# no need for more workers in the proxy mode
worker_processes 1;

error_log logs/error.log info;

worker_rlimit_nofile 8192;

events {
worker_connections 51200; # you might need to increase this setting for busy servers
use epoll; # Linux kernels 2.4.x change to rtsig
}

http {
server_names_hash_max_size 2048;

include mime.types;
default_type application/octet-stream;

sendfile on;
tcp_nopush on;
tcp_nodelay on;

keepalive_timeout 10;

gzip on;
gzip_min_length 1100;
gzip_buffers 4 32k;
gzip_types text/plain application/x-javascript text/xml text/css;
ignore_invalid_headers on;

client_header_timeout 3m;
client_body_timeout 3m;
send_timeout 3m;
connection_pool_size 1024;
client_header_buffer_size 4k;
large_client_header_buffers 4 32k;
request_pool_size 4k;
output_buffers 4 32k;
postpone_output 1460;
proxy_temp_path /home/proxy_temp;
include "/usr/local/nginx/conf/vhost.conf";
}