New Dell XPS 15 9650 4k Video playback choppy gtx1050

I just got an xps15 inch 9650 with the intel Nvidea GTX 1050 4gb video card, I have done all the windows updates and the dell support assistant to update drivers and optimize the system, i also ran the nvidea software and chose for it to search and update the drivers for the video card. rebooted a few times during the process, the computer seems to run ok but when I go to youtube to watch some sample demo 4k footage to take advantage of this awesome screen even if

I rebooted a few times during the process, the computer seems to run ok but when I go to youtube to watch some sample demo 4k footage to take advantage of this awesome screen even if i let it buffer (fast connection too speedtest showing in the 50mbps range), it just chops up on playback.

I saw too in my system specs there is a intel 630 card in this as well assuming thats on the motherboard?   Do I need to tell the computer which video card to use? Is there someting I need to set in the bios, is it maybe just youtube, maybe i can find some 4k video to download to the desktop to check out the new higher res screen?

Mine came from amazon new but has a scratch on the bottom and like 3 minor nicks on the outter edges of the aluminum so i certainly wonder if it was a refurb or return, but at this point I can deal with that if I can get video to playback smoothly.