PTP400 Full not obtaining throughput.

I have two links of the PTP400 4900. The problem i’m having is the throughput that i’m getting on test doesn’t match the throughput on the radio. The way the links are setup is the slave of link one is an end node. The master of link one is at a midpt which is colocated with the master of link 2. 3ft vertical seperation. And the slave of link 2 is an end node. Now this is a lab setup and i still can’t obtain throughput. I have the freqs on a fixed basis and the data rate to 1:1. The radios say i’m getting 17.39M But i’m only reading 13.5M. Any help is appreciated.

Radio saying you have 17.39, and when you push data through you get an actual of just 13.5… Network overhead?

no overhead, just isolated links with a laptop on each end.