Laggy? That's doesn't sound right, especially HDMI. Disable screen mirroring and only have the content play on the TV screen (so your computer is not rendering it twice), maybe?
Or play it with VLC.
Or downscale any 4K content to 1080P. Maybe your CPU/GPU can't handle that resolution.
Or play it with VLC.
Or downscale any 4K content to 1080P. Maybe your CPU/GPU can't handle that resolution.