Yeah, and the integrated GPUs, at least the entry level ones, do suck. My Acer netbook is barely able to play 360p videos, 720p if you're lucky and 1080p - no hope. My cheap smartphone can play 1080p without a single dropped frame.
https://en.wikipedia.org/wiki/Bobcat_%28microarchitecture%29
I've never had an APU but on paper they sound really nice. Intel probably has similar but you may have to be more careful picking your CPU because of market feature segregation.
I would check video drivers, DMA enabled on drives, excess ram or cpu usage by another process(es)
My 7 year old notebook (the one I retired already) had absolutely no problem with videos of this size.