How to fix the problem that the ASP.NET web forms application heavily loads the server and is stupid?

Question

IIS

Good day to all!
Background:
There are two resources (websites) that are written using C#, ASP.NET Web Forms, one older and one later.
There are two web servers, the computing power of which, let's say, is equal.
The problem is this:
An older resource periodically starts to open and hang for a very long time, sometimes after a long wait all of these open, it happens that the waiting time for a response from the server is not enough to wait for a response.
Those. another department is engaged in server support, after a call it turned out that on the server, when accessing the resource, 3 IIS processes are launched, they load the server processor by 100%. But, no particularly heavy scripts are launched when the portal is loaded. After restarting the server, the resource opens.
The problem is that there is no periodicity of freezing, usually the portal works quickly and no freezes are observed.
In general, the question is, since there is not much experience yet, I would like to understand in which direction to dig? There is a suspicion that the other two IIS processes that load the server are two even older resources that are physically located on the same server, but which are not used (at least explicitly, but perhaps there are links to them from a newer resource, which hangs, the problem is that deleting these resources will not work painlessly, since no one has heard of dependency injection and weak connectivity at the time when those resources were written)
Update We
used this tool to see what was loading,
https://technet.microsoft.com/en-us/library/cc7325...
points to the resource where the large gridview lies, in fact there is nothing else there, I was also surprised that if you look at the link below, the XXX resource (sorry, corporate secret), running in three processes, not sure if that's normal, but maybe it's the three domains where the .NET application is running? The screenshot shows that one of the processes uses significantly more memory. The GridView is formed by a rather complex request to the database, but if the database did not respond, then the request timeout would be exceeded...

Answer 1

At the same time, make sure that the project is fully compiled and built, and not built on the fly from open source.
, calm me down, tell me that a complex query for GridView receives the minimum data necessary for rendering, and does not filter it inside itself and paginate it. this is VERY heavy and very bad practice for any heavily loaded services. The database should filter the data and not drive hefty packets back and forth and puzzle the application. filtering logic.

Answer 2

I agree with Dmitry Kovalsky , in any case, you need to either pay off or even demolish those sites that are not used