I have observed the requirements shared by you. I have discussed the issues shared with our development team. Actually, most of things depend upon the configuration on your end.
“what is the scale of the total number of user can use the site?”
- This thing depends mainly upon your server configuration and website configuration.
"also would like to why the CUP usage fluctuate between 50-80 when one person is using and when multiple it hit up 100. "
- This thing depends on number of processors or type of server used on your end.
“also there is no real change in memory… Would like to know why this would be the case”
- Unfortunately, I have not been able to understand this point and why it is an issue.
I also like to add that the issues shared are not directly related to Aspose.Slides for .NET. However, I also like to share that we are working on unification of API for PPT and PPTX in coming product release. This will be certainly increasing the performance of API to a great deal. The new API is expected to be rolled out by end of April 2013. Meanwhile, if you find performance related issue with Aspose.Slides then please share the sample web application with us that we may assess on our end to observe performance related issue with Aspose.Slides if there are any.