Thanks for your contributions guys.
In a nutshell, I have raised a formal ticket on this. Mostly because I have been so frustrated with QA's attempts to wipe off DK2 users when Frontier have NOT officially announced a blanket withdrawal of support for the DK2 (not yet anyway). Sofar they have only withdrawn support for SteamVR as the 'interface' to the DK2 (something that we know already since moving to SDK1.3).
This unwelcome external Stammer/Hitching occurs now and then regardless of the graphic settings (whether or not SS is high or low). I have all the usual things disabled like AO, AA etc. There are several people in this thread who have the same issue, with high spec hardware, so I am not delusional.
Adding SS 2.0 actually does improve things so it is not the performance of my graphic card that is the issue. I am hoping that it's just because the dev team have optimised for 90hz, as opposed to 75hz.
Based on ghcannon's post, I look forward to my CV1 arrival and hope that the issue will be gone once I'm running at 90hz.
Thanks for everyone's input on this. My focus of disappointment has not been with ED, or SDK1.3 which otherwise, is brilliant, it's been the bloody mindedness of QA.
Anyway, I'm off to do some more bounty hunting. I'm giving up trying to work with QA to help ED improve their VR performance. Someone else will have to run with this now as I have probably pi**ed QA-Donny off.
I'm happy to help others on this thread tho, just don't want to deal with QA. My specs are in my sig if you want to compare notes.
Food for thought, I moved my DK2 to the actual HDMI port on my 980ti (I used to use a DP/HDMI adapter). Things seem to have improved slightly, but that could just be a placebo I reckon.