Time to First Byte increased from 0.2 seconds to 2.5 seconds after URL change.

This is a
/etc/nginx/sites-available/default

# You may add here your server {
#	...
# }
# statements for each of your virtual hosts to this file
##
# You should look at the following URL's in order to grasp a solid
# understanding of Nginx configuration files in order to fully unleash
# the power of Nginx. http://wiki.nginx.org/Pitfalls
# http://wiki.nginx.org/QuickStart http://wiki.nginx.org/Configuration
#
# Generally, you will want to move this file somewhere, and start with a
# clean file but keep this around for reference. Or just disable in
# sites-enabled.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed
# examples.
##
server {
	#listen 80; ## listen for ipv4; this line is default and implied
	#listen [::]:80 default_server ipv6only=on; ## listen for ipv6
	root /var/www;
        index index.html index.htm index.php;
        location ~ /nginx.conf { deny all; }
 	# Make site accessible from http://localhost/
	server_name raspberry.lascienzadellospazio.com;
        location ~* \.(jpg|png|gif|jpeg|css|js|eot)$ {
        expires max; }

	location / {
		# First attempt to serve request as file, then as
		# directory, then fall back to displaying a 404.
                #try_files $uri $uri/ /index.php?$args;
                try_files $uri $uri/ /wordpress/$uri /wordpress/$uri/ /wordpress/index.php?$args;
		# Uncomment to enable naxsi on this location include
		# /etc/nginx/naxsi.rules
	}
	location /doc/ {
		alias /usr/share/doc/;
		autoindex on;
		allow 127.0.0.1;
		allow ::1;
		deny all;
	}
	# Only for nginx-naxsi used with nginx-naxsi-ui : process denied
	#requests location /RequestDenied {
	#	proxy_pass http://127.0.0.1:8080;
	#}
	#error_page 404 /404.html;
	# redirect server error pages to the static page /50x.html
	#
	#error_page 500 502 503 504 /50x.html; location = /50x.html {
	#	root /usr/share/nginx/www;
	#}
	# pass the PHP scripts to FastCGI server listening on
	# 127.0.0.1:9000
	#
	location ~ \.php$ {
	fastcgi_split_path_info ^(.+\.php)(/.+)$;
        #NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
	# With php5-cgi alone:
	#fastcgi_pass 127.0.0.1:9000;
	# With php5-fpm:
	fastcgi_pass unix:/var/run/php5-fpm.sock;
        fastcgi_index index.php;
        include fastcgi_params;
	}
	# deny access to .htaccess files, if Apache's document root
	# concurs with nginx's one
	#
	#location ~ /\.ht {
	#	deny all;
	#}
}
# another virtual host using mix of IP-, name-, and port-based
# configuration
#
#server {
#	listen 8000; listen somename:8080; server_name somename alias
#	another.alias; root html; index index.html index.htm;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}
# HTTPS server
#
#server {
#	listen 443; server_name localhost;
#
#	root html; index index.html index.htm;
#
#	ssl on; ssl_certificate cert.pem; ssl_certificate_key cert.key;
#
#	ssl_session_timeout 5m;
#
#	ssl_protocols SSLv3 TLSv1; ssl_ciphers
#	ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv3:+EXP;
#	ssl_prefer_server_ciphers on;
#
#	location / {
#		try_files $uri $uri/ =404;
#	}
#}

This is a
/etc/nginx/nginx.conf

user www-data;
worker_processes 1;
pid /var/run/nginx.pid;

events {
	worker_connections 768;
	# multi_accept on;
}

http {
        # Basic Settings
        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 10 10;
        client_max_body_size 15m;
        client_body_timeout 10;
        client_header_timeout 10;
        client_body_buffer_size  1K;
        client_header_buffer_size 1k;
        large_client_header_buffers 4 8k;
        send_timeout 10;
        reset_timedout_connection on;
        types_hash_max_size 2048;
        server_tokens off;

        ##
	# Basic Settings 2 oldest
	##

	#sendfile on;
	#tcp_nopush on;
	#tcp_nodelay on;
	#keepalive_timeout 65;
	#types_hash_max_size 2048;
	# server_tokens off;

	# server_names_hash_bucket_size 64;
	# server_name_in_redirect off;

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

	##
	# Logging Settings
	##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;

        ###
        # Speed up landing page by caching open file descriptors
        open_file_cache max=2048;

	##
	# Gzip Settings
	##

	gzip on;
	gzip_disable "msie6";

	gzip_vary on;
	gzip_proxied any;
	gzip_comp_level 6;
	gzip_buffers 16 8k;
        gzip_min_length   1100;
	gzip_http_version 1.1;
	gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;

	##
	# nginx-naxsi config
	##
	# Uncomment it if you installed nginx-naxsi
	##

	#include /etc/nginx/naxsi_core.rules;

	##
	# nginx-passenger config
	##
	# Uncomment it if you installed nginx-passenger
	##

	#passenger_root /usr;
	#passenger_ruby /usr/bin/ruby;

	##
	# Virtual Host Configs
	##

	include /etc/nginx/conf.d/*.conf;
	include /etc/nginx/sites-enabled/*;

}

#mail {
#	# See sample authentication script at:
#	# http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#	# auth_http localhost/auth.php;
#	# pop3_capabilities "TOP" "USER";
#	# imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#	server {
#		listen     localhost:110;
#		protocol   pop3;
#		proxy      on;
#	}
#
#	server {
#		listen     localhost:143;
#		protocol   imap;
#		proxy      on;
#	}
#}