Got in contact with the host - they turned of the PHP cache. My site was responding pretty slow at entry. Perhaps i got a little to many big files. Saw another post form you regarding CDN and "WT3C" plug ins.
But i´m not sure how to apply or what to do with this:
Deactivate and uninstall any other caching plugin you may be using (Done). Pay special attention if you have customized the rewrite rules for fancy permalinks, have previously installed a caching plugin or have any browser caching rules (got none) as W3TC will automate management of all best practices.
How to do This>>
Also make sure wp-content/ and wp-content/uploads/ (temporarily) have 777 permissions before proceeding, e.g. in the terminal: # chmod 777 /var/www/vhosts/domain.com/httpdocs/wp-content/ using your web hosting control panel or your FTP / SSH account.
Login as an administrator to your WordPress Admin account. Using the "Add New" menu option under the "Plugins" section of the navigation, you can either search for: w3 total cache or if you've downloaded the plugin already, click the "Upload" link, find the .zip file you download and then click "Install Now". Or you can unzip and FTP upload the plugin to your plugins directory (wp-content/plugins/). In either case, when done wp-content/plugins/w3-total-cache/ should exist.
Locate and activate the plugin on the "Plugins" page. Page caching will automatically be running in basic mode. Set the permissions of wp-content and wp-content/uploads back to 755, e.g. in the terminal: # chmod 755 /var/www/vhosts/domain.com/httpdocs/wp-content/.