This my hardware server:
Processor Intel Xeon E3 1225v2
Cores/Threads 4 cores/ 4 threads
Frequency 3.2 GHz+
RAM 32GB DDR3
Disks 3 x 120 GB SSD


=========================================
the config is nginx.conf:

#user nginx;

# The number of worker processes is changed automatically by CustomBuild, according to the number of CPU core$
worker_processes 4;
pid /var/run/nginx.pid;
error_log /var/logs//nginx/error.log;

#error_log logs/error.log notice;
#error_log logs/error.log info;

events {
include /etc/nginx/nginx-events.conf;
}


http {
include /etc/nginx/mime.types;

# access_log /var/log/nginx/access.log main;

# For user configurations not maintained by DirectAdmin. Empty by default.
include /etc/nginx/nginx-includes.conf;

# Supplemental configuration
include /etc/nginx/nginx-modsecurity-enable.conf;
include /etc/nginx/nginx-defaults.conf;
include /etc/nginx/nginx-gzip.conf;
include /etc/nginx/directadmin-ips.conf;
include /etc/nginx/directadmin-settings.conf;
include /etc/nginx/nginx-vhosts.conf;
include /etc/nginx/directadmin-vhosts.conf;
}
==========================================
config for nginx-defaults.conf:

default_type application/octet-stream;
tcp_nopush on;
tcp_nodelay on;
sendfile on;

log_format bytes '$bytes_sent $request_length';

keepalive_timeout 2;
types_hash_max_size 2048;

disable_symlinks if_not_owner from=$document_root;

server_tokens off;

client_max_body_size 1024m;
client_body_timeout 3m;
client_body_buffer_size 128k;
client_header_timeout 20;
client_header_buffer_size 3m;
large_client_header_buffers 4 256k;
send_timeout 20;

proxy_connect_timeout 600s;
proxy_send_timeout 600s;
proxy_read_timeout 600s;
proxy_buffer_size 128k;
proxy_buffers 4 256k;
proxy_busy_buffers_size 256k;

fastcgi_send_timeout 600s;
fastcgi_read_timeout 600s;

server_names_hash_bucket_size 128;
server_names_hash_max_size 10240;

ssl_dhparam /etc/nginx/ssl.crt/dhparams.pem;

## Anti ddos
limit_conn_zone $binary_remote_addr zone=conn_limit_per_ip:10m;
limit_req_zone $binary_remote_addr zone=req_limit_per_ip:10m rate=5r/s;

================================
config for nginx-gzip.conf

gzip on;
gzip_static on;
gzip_disable "msie6";
gzip_http_version 1.1;
gzip_vary on;
gzip_comp_level 6;
gzip_proxied any;
gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application$
gzip_buffers 16 8k;
gzip_min_length 10;
gzip_disable "MSIE [1-6]\.(?!.*SV1)";

===================================
config for nginx/directadmin-ips.conf:

server {
listen xx.xx.xx.xx:80 default_server; // i hide the ip
server_name _;
root /home/admin/domains/sharedip;
index index.html index.htm index.php;

include /usr/local/directadmin/data/users/admin/nginx_php.conf;

# deny access to apache .htaccess files
location ~ /\.ht
{
deny all;
}

include /etc/nginx/webapps.conf;
}

server {
listen xx.xx.xx.xx:443 default_server; // i hide the ip
server_name _;

ssl on;
ssl_certificate /etc/nginx/ssl.crt/server.crt.combined;
ssl_certificate_key /etc/nginx/ssl.key/server.key;

ssl_session_cache shared:SSL:10m;
ssl_session_timeout 5m;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers HIGH:!aNULL:!MD5;
ssl_prefer_server_ciphers on;

root /home/admin/domains/sharedip;
index index.html index.htm index.php;

include /usr/local/directadmin/data/users/admin/nginx_php.conf;

# deny access to apache .htaccess files
location ~ /\.ht
{
deny all;
}

include /etc/nginx/webapps.conf;
}

===========================
config for directadmin-settings.conf:

empty

===========================
config for nginx-vhosts.conf

server {
listen xx.xx.xx.x:80; // i hide the ip
listen 127.0.0.1:80;
#listen [::1]:80;
server_name $hostname xx.xx.xx.xx; / i hide the ip

root /var/www/html;
index index.html index.htm index.php;

#Support UserDir (~/user/)
location ~^/~(?<userdir_user>.+?)(?<userdir_uri>/.*)?$ {
alias /home/$userdir_user/public_html$userdir_uri;
index index.html index.htm index.php;
autoindex on;

location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
include /etc/nginx/fastcgi_params;
fastcgi_index index.php;

#try_files does not work after alias directive
if (!-f $request_filename) {
return 404;
}

fastcgi_param DOCUMENT_ROOT /home/$userdir_user/public_html;
fastcgi_param SCRIPT_FILENAME $request_filename;
fastcgi_pass unix:/usr/local/php54/sockets/$userdir_user.sock;
}
}

# Pass all .php files onto a php-fpm/php-fcgi server.
location ~ \.php$ {
try_files $uri =404;

fastcgi_split_path_info ^(.+\.php)(/.+)$;
include /etc/nginx/fastcgi_params;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_pass unix:/usr/local/php54/sockets/webapps.sock;
}

include /etc/nginx/nginx-info.conf;
include /etc/nginx/webapps.conf;
}

# HTTPS server
#
server {
listen xx.xx.xx.xx:443 ssl; / i hide the ip
listen 127.0.0.1:443 ssl;
#listen [::1]:443 ssl;
server_name $hostname xx.xx.xx.xx; / i hide the ip

ssl on;
ssl_certificate /etc/nginx/ssl.crt/server.crt.combined;
ssl_certificate_key /etc/nginx/ssl.key/server.key;

ssl_session_cache shared:SSL:10m;
ssl_session_timeout 10m;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers HIGH:!aNULL:!MD5;
ssl_prefer_server_ciphers on;

root /var/www/html;
index index.html index.htm index.php;

#Support UserDir (~/user/)
location ~^/~(?<userdir_user>.+?)(?<userdir_uri>/.*)?$ {
alias /home/$userdir_user/private_html$userdir_uri;
index index.html index.htm index.php;
autoindex on;

location ~ \.php$ {
fastcgi_split_path_info ^(.+\.php)(/.+)$;
include /etc/nginx/fastcgi_params;
fastcgi_index index.php;

#try_files does not work after alias directive
if (!-f $request_filename) {
return 404;
}

fastcgi_param DOCUMENT_ROOT /home/$userdir_user/private_html;
fastcgi_param SCRIPT_FILENAME $request_filename;
fastcgi_pass unix:/usr/local/php54/sockets/$userdir_user.sock;
}
}

# Pass all .php files onto a php-fpm/php-fcgi server.
location ~ \.php$ {
try_files $uri =404;

fastcgi_split_path_info ^(.+\.php)(/.+)$;
include /etc/nginx/fastcgi_params;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_pass unix:/usr/local/php54/sockets/webapps.sock;
}

include /etc/nginx/nginx-info.conf;
include /etc/nginx/webapps.ssl.conf;
}

====================================
config for directadmin-vhosts.conf:

for individual clients i think not matter it empty there.

=================================
config for: nginx/nginx-info.conf

location /nginx_status {
# Enable nginx status page
stub_status on;

# Disable status page logging in access_log
access_log off;

# Allow access from 127.0.0.1
allow 127.0.0.1;

# Deny all the other connections
deny all;
}
=========================
security_mod disabled now. but the config is nginx-modsecurity-enable.conf:

ModSecurityEnabled on;
ModSecurityConfig /etc/nginx/nginx-modsecurity.conf;

============================