So I have finally narrowed down some issues that have been outstanding on my rigs and thought this might be useful to others. I had been having unexplained sporadic but frequent cpu spikes in Cubase/Nuendo for awhile but could never track down the exact cause after a lot of troubleshooting. My asio meters would bounce to extremes. Also occasional glitching in the network audio. Was very frustrating, when the system cpu was always normal and the machines checked out fine on all DPC latency tests. VE Pro at 1 buffer would stream fine but the asio meter would spike more. When at 2 buffers I would get less asio spikes but VE Pro streaming could get glitchy. I tried all combinations of audio buffer and VE Pro buffers. So that got me to thinking the issue was somehow related to the network card and some kind of priority issue. I
So as soon as I turned off Interupt Moderation in all my Intel and Realtek NEC's things were absolutely perfect! It was enabled by default. So simple! I can now set my audio buffer down to 64 samples and VE Pro to 2 buffers and everything plays perfectly! I will probably settle at 128.
So if anyone is having similiar issues go into your network Configure panel under Adavanced (Windows) and look for anything related to Interrupt Moderation and disable it; I set Interupt Moderation Rate to off as well. Also a good idea to turn off any Green Ethnernet/energy saving options in the NEC too.
Hope that helps.