The z3 works smoothly on everything including live stream feed even the 4k live stream is smooth.

But the 4k recorded video on the microsd is laggy, it does not matter whether it is 24 fps or 30 fps, 3.8k or 4k.
All 4k video options produce laggy video on the microsd.

Still 2.7k is enough and even has extra digital zoom.

I just want to ask if the 4k video footage will ever be fixed?

The 4k recorded footages are actually fine.

Bootcamp windows 10 just had lags on viewing the 4k video.

Thanks please delete this thread

Glad to know you figured out the issue, 4K has high demand to computer and system, thanks for updating, it may be helpful for other users.