Do you have a sample configuration?
depends on what setup you have, if you have a GPU that supports DXVA2 you can go with that for scaling, otherwise sticking with softcubic and Catmull seems to reduce a lot of load.
as for the rest of the settings.
(http://img35.imageshack.us/img35/4417/q702.png)
(http://img822.imageshack.us/img822/2336/8nk6.png)
(http://img28.imageshack.us/img28/5534/ugq0.png)
a few things to note:
the buffers works as what it suggests, with a larger buffer space it decodes the frames in advance, it then buffers the decoded frames.
-- too large buffer space can cause dropped frames due to unused buffered frames, but it won't cause stuttering unless your CPU can't keep up.
for the sharpest and cleanest image though jinc still does best in upscaling, catmull on downscaling.
i'm using the maximum quality, with all trade-offs disabled due to what my machine can handle.
jinc3 with active ringing filter for upscaling, catmull-rom for downscaling, 24cpu and gpu buffers, smooth-motion fully enabled(it doesn't interpolate, it rearranges frames so it doesn't have any judder).