My Lab environment consists of a Supermicro Server with the mainboard X10SLM-F.
There is installed a virtual free Kemp Loadmaster (VLM-200) and some virtual MS Server 2012 R2 Webservers.
When I download a file from a webserver, which is a Kemp virtual service, the troughput will never be more than 200 KB/s.
When I download the file direct from the Webserver, there is a troughput grater than 40MB/s.
The virtual Kemp and the webservers use the same physical network interface.
I cannot find any helpful information into the log files.