How to build my internal network using Tata V-SAT

Hai
I am a sys engg.
We use internet connection through V-SAT device and i have 2 lan cards installed on my server system. One is for external network and another for internal network.

In our another branch they are also using V-SAT connection and they use only one lan card in the server and they plug cat5 cable directly to switch.

Which setup is fast for internet connection?