Ok today did some more tests with my 4K content which is stored in my NAS storage. The issue is not with the TV but my Synology DS214se NAS which has Plex (by the way as per many reviews this is the best app for all sharing the files over the network) unable to transcode the files. If I playback the same file using attached HDD on the TV directly then the TV plays it in a jiff without even pausing. So now looking at other alternatives and looks like maybe I need to build a HTPC which can do this or maybe the Nvidia Shield TV 4k.