Sitefinity 4.x requires 500MB+ application pool memory for the backend pages to function properly. If you have allocated less then 500MB, Sitefinity will work, but you might experience some performance issues when browsing the backend pages of the CMS. This is because all of the modules are put in one assembly - Telerik.Sitefinity, and the whole assembly is loaded into the memory. However if you are expecting a lot of connections I can suggest setting up Sitefinity in Network - Load Balanced environment. Please consult the following article:
Also when deploying your site ( as it seems to be needing quite a lot of resources to meet the demand ) I can suggest you is to review the following page, which provides few tips for optimizing performance:
Please note that If caching is turned on then the page output should be many times faster.
the Telerik team
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