what is the Best approach to update the dashboard with server data?

I implementing dashboard kind of functionality. As shown in attached image

http://ift.tt/1zYOWH9

For now I am continuously updating the dashboard with server info by calling the webservice after every 4 seconds.

So I am updating section values in fig (a). after every 4 seconds.

If i select one of the section. I am supposed to show the detail list view of the section. For that I am calling to web server again. Fig (b)

I am using the table view inside 0th row/cell of every section. Also once I select the section it should continously update the server changes inside inner detail list too.

To show details list view I am reloading section

So I want to know what is the best way to implement this scenario.

Any suggestion are highly appreciated.

Thanks