The Website Slows Down at Checkout A LOT !

Dear Fellow Nopcommerce Addicts,

Please visit my website http://www.mgactivewear.com running on SmarterAsp Hosting
with Shared Semi Advance Plan with 2 GB Ram .

I have worked hard under the hood and optimized page speed for fast page loads.

But I am facing problem of website slowing down for checkout process. Or when there is something thats needs to be pulled from server the site slows down a lot and gives a bad experience.

Slow Down Instances :
1) Check out Process
2) Add product from Home Page Featured Item
3) Click on Product Quick View on Featured item on home page (magnify icon)

As per SmarterASP tech team the site is loading fast and nothing more can be done.

I request if you can browse the website as a regular customer and advise fixes to best the performance to drive conversions at checkout.

FYI : I am using One Page Checkout

Thank you .