Hello. So first of all I will tell you my story.
I watch movies via Kodi. I bought Android TV (4K,HDR( with speakers and amplifier (all kind of dts hd,truehd audio stuff) connected it and try to watch movies. (KODI – for Android TV)
Start to play movie it was nice, it played fine HDR 4K, buttery smooth via TVs hardware but then there was problem with audio, the TV HDMI ARC limits for only Core DTS and Dolby Digital so no DD+ nor the DTS HD,TrueHD.
I read a lot of articles, and its its looking like no-go for me with current hardware, (Perfect image “check” but without the audio (dts hd on nice spekers) 
Then someone tell me that If I have PC that I could counnect ot PC then that will solve the codec limitatnions so “Image and Audio”
As I have the TV connected to my PC I just configure the Kodi for Windows and Try to watch the same movie and, It stars 4K(NO HDR) with Full Audio support but image stuttering. (PC specification: Core i5 3570 / 16GB / Radeon HD7870)
I read that yeah I would get the full audio support via HDMI but then I need the propper hardware support HDCP 2.2 with the hardware support codec to play smoothly the 4K HDR videos.
Another read of the articles says that 4K smooth is achived by new cpus Intel 6th or 7th generation, Maxwell,Pascal gpus gtx 900/1000 or AMDs RX 400/500 Series the question that I have for you guys is:
1. Do I need to upgrade my CPU+GPU with automaticly requirest to change motherboard, rams for ddr4 besicly all PC, or can I just upgrade the GPU? (eg. Radeon RX 580?) will this be fine for smooth playback (gpu have hdcp2.2,hdr support,hardware codecs etc)
2. Will KODI detect the HDR content (Android TV version detect) on my Windows version of KODI? (considering I will buy the RX 580, connect it via HDMI 2.0b have windows 10 CU with have HDR support?)
Please help me as I I have no strength anymore, its so exhausting to make it work.
What are your experiance with this anyone play 4K HDR Smoothly with DTS HD or TrueHD on your PC?