Website loading too slow with using XML file

Question

We have a problem in our website, it is loading too slow. We use xml file to display a grid of infos with image and details, but the page load too slow, we make a test and this are the results:

 

 https://gtmetrix.com/compare/OUSJcnwv/Tk5m9fau

 

we compare 2 of our pages and both are loading slow.

Do anybody have an idea why the server response too slow. We make a tracert test and it seems to be fine.