I have seen thru some time that the old vSphere C# Client's search function has become slow, after a little research i found that the VMware VirtualCenter Management Webservices is not getting enough resources.
I have checked different installation at different customers and I found that it don't get the recommend memory.
VMware has a Knowlegde Base article that describes the recommendations, and where you find the current values, so it can be changed. KB2021302
After changing the value and restart of the services, I found that the search function was a lot quicker, and i also think that there are other function that works better.
I haven't check the other services if they also may need more memory, since I was only looking for performance enhancement i the Search function.