i am using drupal 4.7 which is running perfectly fast on DV 3.5 Site www.2knowmyself.com
now media temple is closing 3.5 and i am forced to move to DV 4.0

i setup a test site on the new server which can be accessed through that ip:

the new site is terribly slow , browse for few moments and at least one page will take 8 seconds to load compared to 0.5 second for the original site

both servers have 2GB of ram , the only difference is in the new version of PHP and Mysql

how can i fix that slow response issue?