I am very interested in your problem, or the problem of your new PC exactly. Would you please first check Davinci Resolve working normally? Or in other words, use other PC to playback the 4K video file, will it playback normally on other PC? What kind of players are you using to playback 4k video? Does it utilise the GPGPU to accelerate or you have choose the proper output method? Is the GPU driver installed correctly?
Oh, sorry, what does "It doesn't seem to matter if I use VLC, WMP, Windows 10 "film & tv" player or quicktime" mean? Those players would play 4k video without problems?
Thanks for the reply
I don't know if Davinci Resolve uses the GPU directly to help process/accelerate the video or not while processing, but I think it might by default because it would not even work with my old PC with a 1GB card. I also use Sony Vegas for editing and it has an option to use GPU while rendering but I usually turn it off because it does not help a lot.
When I said "It doesn't seem to matter if I use VLC, WMP, Windows 10 "film & tv" player or quicktime" I meant that all of them will sometimes stutter or lag while trying to playback video. I have not had a chance to try the videos on another PC yet. The funny thing is it is not all the time this happens - sometimes I can play video smoothly, and sometimes it will lag badly, even 1080-60p video.
There is one clip in particular that seems to be giving me issues this week, so I am going to copy it to a USB and try it on my work computer, and HP which is not near as powerful as my home workstation.
I keep the drivers updated whenever a new update comes out from AMD. I am still puzzled why the CPU does not work harder when playing video, since this is a CPU intensive task.