That doesn't sound like a memory leak to me - just not enough information for me to make that conclusion -, but the described symptoms may still indicate a problem.
Before doing anything, have a look at @VincentGaliana's answer, and try clearing out your EventQueue and PublishQueue tables. If the issue persists, proceed with with the below.
To troubleshoot the issue further, first try the following:
- Perform the renaming of your IIS site
- Verify that all of your permissions are set correctly for your website folder (this should switch over automatically, but this is just to make sure that nothing weird happened)
- Clear out all of your Temporary ASP.NET files
- Recycle the App Pool from IIS
- Try pinging the site again.
If, at this point, memory spikes for more than a few minutes (longer, if your site typically has longer initialization periods) then try the following analysis steps:
- Allow the site to continue initializing (with the high memory usage)
- Look in the data folder to see if Sitecore is writing to its logs and report any errors that you see
- Check to see how SQL is performing (whether running locally or not). If possible, connect to the SQL Profiler and check to see what kinds of queries (if any) are executing
- Test out the connection to and availability of MongoDB from the server (using RoboMongo or another tool), and, if you're running MongoDB locally, check the activity of the MongoDB process
It is likely that one or more of the above will help give you an indication of what is causing your memory to spike. If none of the above pan out, I recommend attaching JetBrains dotMemory to the process to analyze exactly where the memory is going.