I got a DK2 from a friend to try at home, all installed well on Runtime 1.4 and keeps at the maximum 75 FPS. However, there is extreme judder and lag in the Oculus Home app. I can also describe it as ghosting. It's most visible at the white buttons here https://youtu.be/t_pmKm-b3gI?t=3s
It goes completely away in Oculus Home if the USB plug is unplugged and then plugged again (Oculus home restarts). This part of the video shows it working very well after re-plugging (keep in mind the smearing visible in that is due to the 30FPS that the phone's camera records the video at) https://youtu.be/t_pmKm-b3gI?t=2m52s
It does not matter whether it is USB 2.0 or 3.0. This is not a camera issue, since it occurs also when the camera is unplugged. I am thinking this might be due either to bugs in the rotational tracking (with Asynchronous Timewarp?) or the DK2's screen defaulting to 60hz and still receiving the signal at 75hz. It is very annoying, since all is well and perfectly smooth if you keep your head still (e.g. in Dreamdeck), but once you move your head, the lag/judder/ghosting is terrible.
The trick with unplugging and plugging again works only for Oculus Home, but not for Dreamdeck.
I would be grateful to fellow DK2 owners for any tips on how to fix this.