Solution
Hosting Requirements For Magento
Magento is an ecommerce script that is performance intensive because it runs very complex database queries. As such, it should only be run on�dedicated servers. Varien, the creator of Magento, has a few resources to help with Magento's performance issues:�performance and optimization group,�Magento wiki,�forum community,�an optimization whitepaper and�dedicated support (paid).
The actual performance of Magento varies from store to store, and running your own data on a test installation of Magento is the best way to test performance before going live. We recommend that Magento be run on nothing less than our dedicated server.