Hello Linjo, thank you again for your help...
I've installed recent nVidia driver as proposed with no significant change in user experienced FPS-performance.
6 months ago, I also delivered an additional Server with same specs - equipped with nVidia Quadro 6000 instead - and configured as vSGA to share GPU-capabilities among multiple virtual machines. Server is currently productive - 20 users are sharing same resources - implementing sVGA improved User Experience significantly.
In this test i compared vSGA and vDGA with regard to User-experienced FPS - this is the counting factor for users. 100fps on a machine do not matter if 10fps visually arrive at a zero client. The comparisson shows that vSGA is nearly synchronous to effective machine-related FPS. As seen vDGA delivers 6-8 fps. One could think that a direct-connected PCI-device noticeably reduces CPU load to give more capacity for PCoIP Encoding...I'm still wondering if i made any mistake in configuring vDGA...
Test has been run on same ZeroClient