Mystery
I repeated measures with your video at your profile settings.
SVP 3.1.6 official old libs: 33% CPU load, smooth playback
SVP 3.1.6 new libs: 48% CPU load, jerky playback
SVP 3.1.6 new libs with "analyse.main.search.width = 0;" in override.js: 32% CPU load, smooth playback
I have core i5-3570K + GTX 66-Ti. I used avisynth 2.5.8 MT SVP Edition.
And yes. It is strange when I got jerky playback with 48% CPU load with new libs. I will continue to explore this problem. Thanks for your bug report.
P.S. I encreased threads number from 7 to 11 and I got smooth playback at these settings with new libs. CPU load was 51%.