Hello, I am Xiao Qi from http://DnnModule.com. Yes, the store module on this site (http://www.shaghayegh2.com/) is our product. It is called as
"Classified Pro 8.2 - DNN 7.3 Store & Auction & Classified Ads & Slideshow module".
As the "Classified Pro" module developer, I like to answer below questions:
"5. do the modules use caching?"
Yes, we use cache for frequency-used data, like departments/categories, these data are used everywhere in module so we cache it. But these are little data, and only consumes 1-2kb memory space.
"5. do modules use caching properly?"
Sure, I believe that. We are professional DNN module developers and have worked on DNN for about 10 years. Check
http://DnnModule.com for our modules.
"5. do modules properly use Client resource libraries"
We mainly use JQuery (and JQuery UI) libraries, which are part of DNN.
As the load speed of this Iran site, I have a few suggestions:
1. The newest version of our module is "Classified Pro v8.2", new version added a few indexes for data tables which are used in "Classified Pro" module. I think it helps a bit to improve the data access speed. But not too much, just a bit.
2. It seems there are some problem about the MS Sql Server database configurations in your existing store site (http://www.shaghayegh2.com/). For example, as you will see in your previous error report.
"could not allocate a new page for database 'shaghayegh2_com_' because of insufficient disk space in filegroup 'PRIMARY'.",
"The transaction log for database 'shaghayegh2_com_' is full due to 'ACTIVE_TRANSACTION'. "
These errors should not occur for a good-running database, so you need to ask a MS Sql server expert to help to check its configurations.
I fully agree with @Sebastian Leupold. "Please be aware that performance optimization is an overall process, affecting all components involved. ", it is a system work to improve DNN site loading speed. And since DNN needs to take care of too many things (DNN is the most powerful open source CMS platform in the world, but powerful requires resources), so it can't load more quick when compare to other simple PHP applications. So in your case, we can't expect to get a 2-3 times load fast speed, but can only expect to get a 30% - 40% improvements.
Good Luck.