1080p 60fps video playback choppy/laggy?

[SultanGris]

Any video/computer experts on here who can tell my why i get occasional choppy playback for the 1080p 60fps videos on my desktop and one of my newer laptops but they play just fine on an old antique laptop with much worse system specs? makes no sense to me, lol! Ironically 4K videos play much smoother but i dont have a 4k capable display. Ive tried multiple players on both computers with the issue with not much change. They should both easily be capable of smooth playback as their system specs are way above what the old laptop that plays smoothly has. I dont get it. Tried a couple more of my friends laptops and was choppy on one and worked good on the other. Its not the file cause the same file works on certain systems and if I upload it to youtube on the choppy playback systems it plays smooth online. Anyone else have this problem? thanks.