Bravo, Windows X! After installing FP on the second PC (control PC), I had a listen. It sounds as if my DAC had been upgraded to a much more expensive one. Now the setup is very much to my liking: sibilance (high noise) is mostly gone to the extent that I can freely turn up the gain knob without hurting my ears. Images are bigger, taller, deeper, and more palpable. Sweet and dynamic, very happy!

Contributing components and “ingredients”: Windows 8.1/Fidelizer Pro/Jplay/BHE/generic NIC/generic 16gb ram laptop as control PC.
Windows Server 2012 r2 core/AO/Jplay/Fidelizer Pro/generic USB to gigabit Ethernet adapter/generic 16gb ram laptop as audio PC.

Additional tweaks: battery or linear PSU powered Cisco switch (thanks hillbear), minimized tx & rx buffer settings (thanks Peter C, Fran, MJ), optimized BHE settings (thanks Minorisuke & Fran).

There are rooms for improvements: laptops to be replaced by fanless PC, audio grade NIC & USB cards, SSD, PPA or JCAT cables, just to name a few. But for now, the current setup really works wonders for me. Couldn’t be more grateful to the genius developers of Jplay, AO, FP, and BHE.