Overload Issue in FSCT

I'm running FSCT to check users overload in Cent OS.

Now after the setup has been changed, no. of user overload has become less.

Initially overload used to be around 2200 users and the value has decreased to 800 users.

Can anyone suggest, what might be the cause. Seems something is missing in the setup.

Setup specifications: 
Mem: 8TB
Speed: 1000Mbps
CPU: 4

We are having 4 windows clients.

Thanks in advance.