Problem with Load Speed with my new dedicated hosting

[eluser]Unknown[/eluser]
Hi all, I'm using codeIgniter for 2 years, and everything was fine until now. I recently made a migration to a new dedicated hosting, with CentOs and Parallels Plesk Panel 11.

First of all i had problems with my .htaccess

It were like that:

<IfModule mod_rewrite.c>



RewriteEngine On
RewriteBase /


### Canonicalize codeigniter URLs

# If your default controller is something other than
# "welcome" you should probably change this
RewriteRule ^(home(/index)?|index(\.php)?)/?$ / [L,R=301]
RewriteRule ^(.*)/index/?$ $1 [L,R=301]

# Removes trailing slashes (prevents SEO duplicate content issues)
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.+)/$ $1 [L,R=301]

# Enforce www
# If you have subdomains, you can add them to
# the list using the "|" (OR) regex operator
RewriteCond %{HTTP_HOST} !^(www|subdomain) [NC]
RewriteRule ^(.*)$ http://www.warhammerfantasy.es/$1 [L,R=301]

# Enforce NO www
#RewriteCond %{HTTP_HOST} ^www [NC]
#RewriteRule ^(.*)$ http://warhammerfantasy.es/$1 [L,R=301]

###

# Removes access to the system folder by users.
# Additionally this will allow you to create a System.php controller,
# previously this would not have been possible.
# 'system' can be replaced if you have renamed your system folder.
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ /index.php/$1 [L]

# Checks to see if the user is attempting to access a valid file,
# such as an image or css document, if this isn't true it sends the
# request to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]

</IfModule>

<IfModule !mod_rewrite.c>

# Without mod_rewrite, route 404's to the front controller
ErrorDocument 404 /index.php

</IfModule>

The problem with that code was an error when there was no use of index.php in the urls.
That printed this error: "No input file specified."

After that, i read a thousand of forums and found that solution, a new .htaccess

AddHandler x-httpd-php5 .php

AddDefaultCharset utf-8

Options +FollowSymLinks
Options -Indexes

DirectoryIndex index.php

RewriteEngine on

RewriteBase /

RewriteCond $1 !^(index\.php|images|robots\.txt|public)
RewriteCond %{REQUEST_URI} !\.(css¦js¦jpg¦jpeg¦png¦gif)$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php?/$1 [NC,L,QSA]

With that one, the website works, all friendly urls works (without index.php).
However the problem is the load speed of the page have become extremly high, 20 seconds.
http://www.warhammerfantasy.es/generador/lista/19358

I noticed that certain pages had faster load speed, most of them with no Database calls.

Any clue about what's happening or how can i solve that?

I don't know if it's apache configuration problem, mysql configuration problem, I'm noob in server configuration stuff.

Thanks in advance for your help.

Note that the website has a wordpress blog and a phpbb3 forum that works like a charm.
http://www.warhammerfantasy.es/blog/
http://www.warhammerfantasy.es/foro/

[eluser]Unknown[/eluser]
Removing a few heavy mysql queries, the loading speed has been reduced.

That points me to think that there is a problem with the mysql queries speed.

¿How should I configure my plesk panel to improve that?

Thanks!