[mclingo]

i'm not using windows 7. i'm using windows 10 latest creators. i was using windows 7 on the HTPC before going 4k, i'm now using Windows 10.

before going 4k. i was using windows 7+kodi with no external player i had years of trouble free playback.

but as you say windows 7 is old and i very much doubt that it would support 4k+HDR playback. i might try it for a giggle :-)

everything was working but now its not :-(
only thing i messed about with was trying to get HD audio working via another hdmi port on the 1050ti (lets call it HDMI 2) connected to my amp. while another port on the 1050ti (lets call it HDMI 1) was connected to the tv.
this did not work no matter how i configured things. possibly HDCP 2.2 kicking in and messing things up.. i dont know.

i'll get everything hooked up with the new amp later tonight and do a fresh install again and see what happens. new amp is 4k, HDR and HDCP 2.2 compliant.

There can be quite a few variables for getting smooth playback as you know, to help rule things out i'd start with a fresh install of MADVR, LAV filters and MPC-HC, then configure other players you might want once you've got that working as it should.

 - When you've got MADVR up and running remember to check DIRECT3D 11 for HDR but leave FSE unticked. (remember to turn it off in DS as well and turn on DIRECT3D11 in DS too) You'll also need a custom res for 1080p23 and 2160p23 created in MADVR but dont bother trying to do this in the NVIDIA drivers, there shouldnt be any need.

 - With regard to KODI DS. Set your GUI as 2160p but enable windowed mode.

 - Make sure you have refresh rate switching enabled in MADVR but disabled in DS

 - leave all other settings are default in MADVR.

 - LAV - just use COPYBACK for now, you can experiment with others later.

 - set your desktop as YBCR 4:2:2 for now, just until you get everything setup, you can play around with 4:4:4 and profiles and other stuff once you've got a stable system, setting it llike this should prevent any switching or bandwidth issues that might crop up.

I also have an NVIDIA 1050 which I use in my Music Studio, its also running a 4kTV. I dont use this for movies but I could set this up if you need me to test anything but it might be couple of days before I get chance.

BE AWARE - not all HDMI 2.0 cables are what they say they are, dont buy cheap, some are only 10gbps but still have HDMI 2.0 spec, you need high quality 18gbps as a minumum and ideally they need to be under 3 meters.

Sure you know most of this though fella, hope things go well this evening !