Speed problem

[mito]

Hi,
i am having speed problems with zen cart and iam not sure
where s problem. Shop is advertising more than 2000 items and sometimes query took more then 15 seconds during highest traffic, later when it calms down query takes from 2-5 .....

How can i find out if its problem of server low-performace or its somewhere else.

link to shop: www.aashop.sk

Thanks

[Kim]

well- part of the problem might be you have at least one image on your front page that is over 1400k!