Changed the interface to an Intel PRO/1000
Download speed has gone up a little bit, but still only 27Mb/sec, while my connection should be 120Mb/sec.
I do get the full 120 Mbit if I plug the cable directly into my workstation.
Somehow pfSense on Hyper-V seems to limit the download speed
I hope someone has a solution for this, I really like pfSense, but I cannot use it if I only get 1/5th of the bandwith I pay for.