Might sound crazy, but what Monitor/resolution are you using? I had a fairly intense project that ran fine on 4.6 with 0.4.2 run time. But absolutely wouldn’t run without judder in Direct or Extended mode under 0.4.4 runtimes. I still can’t get that performance again in 4.7. Now, if I build from the ground up again with the “new limitations”, I’m fine, and I love the new VR Preview mode.
What was strange during my search for a solution. I could easily hit 75fps or better in Extended mode, but only if I didn’t flip my second monitor display. This essentially made the rift display it’s image upside down. Strangely it ran great, upright it juddered. This is also Win 8.1, couldn’t get the scene to run properly at work on a much more expensive machine with a GTX 980 on Win 7. Granted that machine also had BS corporate ware on it too, so who knows if that had an impact.