1080p Stuttering on 4k display - Gemini Lake N4100 + UHD 600 Graphics

I'm testing out LibreELEC right now, having some video stuttering issues.

Gemini Lake N4100

UHD 600 Graphics

4GB DDR4 at 2133mhz

HDMI 2.0a

LibreELEC 9.0.1/Kodi 18.1

Playback of 1080p videos on my 4k display over HDMI is stuttering. I have my display rate switching enabled and match display enabled, but it still seems to be struggling. Even if I force my display down to 1080p, I'm still seeing staggering in panning shots.

I know 4k is a little high end, but that's the display I'm stuck with and I am only trying to play 1080p content.

Is there anything I can do to get this playing smoothly?

Any help deeply appreciated.

I've tried various configurations, so far limiting the kodi resolution to 1080p/30hz seems to give the best performance but I'm surprised that it's not able to leverage the power of the chipset, it's quite capable of playing 4k video in Windows.

Quote from jbinkley60

This may be the answer. Kodi 18.2 was released on April 22nd and they have fixed the microstutter problem on Intel platforms with interlaced content.. Specifically they call out "VAAPI on Intel has gained some corrections for interlaced content that toggled interlaced flags during playback, and therefore caused stutter by reconfiguring the decoder." I personally am looking forward to the next release of LibreElec with this fix. LibreElec updates generally follow Kodi releases by a short period of time. BTW, I am seeing the same issue on an Intel NUC 8i7BEH.

Maybe but none of my content is interlaced

Quote from smp

This makes no sense and 30Hz mode should never be used.

What refresh rates are listed as available for 3840x2160p?

refresh rates all the way up to 60hz are offered, but still the decoding performance is very unstable be it at 1080 or 2160, full frame pans introduce staggering and frame drops. Maybe it's an audio clock sync problem?

Sync playback to display makes no difference for me. I also noticed that disabling Hardware Acceleration also seemed to have no effect on performance, which makes me wonder if hardware acceleration is even working at all.