4790K @ 4.6Ghz and a GTX 1070. I watch 4K @ 48FPS HDR content without any lag. Took me a while to get the settings right. You don't need 60FPS with 4K, 48FPS works great too, here are my settings for MPV. You must be using the paid version though, create a new profile for 4K content, for 1080p content use your own working profile if you want:
Settings 1: https://i.imgur.com/LIxztsk.jpg
Settings 2: https://i.imgur.com/XHXI2KN.jpg
Also I have outer lighting DISABLED, just right click SVP, go outer lighting, and click DISABLED. Then go video frame and un-tick "detect and cut off black bars", you don't need that, especially for movies/shows that change ratios.
As for MPV, you need to create a mpv.conf in the MPV configuration folder, make sure the bold area is your username and you have hidden files enabled:
C:\Users\YourUsernameHere\AppData\Roaming\mpv
Use notepad, then change the extension to .conf
Here is what you type in the notepad document below, and save it in the MPV directory I just typed two lines above, create that mpv folder if it doesn't exist in Roaming:
profile=gpu-hq
fbo-format=rgba16hf
gpu-api=vulkan
gpu-context=winvk
hwdec=nvdec
vo=gpu
spirv-compiler=shaderc
priority=high
scale=ewa_lanczossharp
cscale=ewa_lanczossharp
dscale=ewa_lanczossharp
dither-depth=auto
correct-downscaling=yes
sigmoid-upscaling=yes
deband=yes
deband-iterations=4
deband-threshold=50
deband-range=16
deband-grain=0
vd-lavc-dr=yes
vd-lavc-threads=16
hdr-compute-peak=yes
