I play my media from a brand new portable hdd (WD's My Passport). Kodi and SPMC as media players. It should play movies and albums smoothly. That's what the USB port is for. I'm not going to change the method
Plugging it straight to my LG 4K TV has been gives me no problem.
It is ridiculous that a TV is better at playing media than a product that was designed specifically for it.
And if you think it's just me, google "mi box stutter" (you won't need to type it all, it's such a popular search, the engine predicts it) .
From now on, I'll advice everyone to not buy a Mibox.
When I had my MiBox, it handled content over SMB up to 4K in Kodi without stuttering (Ethernet not wifi) 4K only had to buffer for a moment if I fast forwarded