We are unsure why this is happening its a first. 3.6 did not have the issue at all. it seems like whenever anyone is clicking off our category list the site response time has become so slow its painful! Is anyone else feeling the larger amount of drag time on 4.0 or is this something new?
 
http://www.gizar.com

Check the attachment file.
 
The load time of 24 seconds is due to PHP.
 
I downloaded your page in under 5 seconds but was waiting 24 seconds for PHP to finish.
 
I advice you to look at your server not at viart package.