MVC Ajax Calls Getting Very SLow performance while in Domain

Question

We are trying to draw two graphs for given excel data, Graphs are working fine without any issues but the problem is when we are hosting into IIS server , We are getting very low performance if we are using machine ip address / domainsname in the same system but if we are using localhost its working fine.

For Example Published machine if I am using,
12345.example.com/Graph - Its Very Slow ( 12345.example.com).
10.10.10.10/Graph - Its also Very Slow (using IP)
Localhost\Graph - the same above published machine while using IIS its very fast and giving good performance.

Is there anything do I needs to change anywhere related to host/IIS/firewall

Notes: From users machines what ever ip or domain name its loading takes huge time.