But this is how the caching works. When you have a cached page, Asp.Net serves the cached html, which was previously rendered. This means that the entire lifecycle of the page is skippen - you already have the cached html that you want to serve to the browser. Using cache substitution controls can make certain parts of the page dynamic, meaning that you can invoke the session there.
The performance really depends on the things you have on the page. For example, if the controls do too many operations and retrieve too many data, then yes, 10 requests can block the server. In my opinion 10 requests are too little to crash the entire IIS though.
Can you provide some additional information on the issue?
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