Same video conversion file, GPU works on one machine but not the other

Hi,

I a newbie and asking a question on behalf of my son.

We have an Asus PC, I7-6700,, GTX 950 2GB and when I export the file cpu and gpu are utilised (as seen in the windows task manager).

I just purchased an Asus Laptop, i7-770HQ, GTX 1060 3GB, cpu utilised but the gpu is not.

The pc will process the video in about 6 minutes, the laptop in about 16 minutes.

The project renderer shows CUDA on both.

The file is being exported in Format H264 and present is High Quality 1080p HD.

I've read that gpu is only used on certain effects, but here I'm encoding both files exactly the same,

Surely  the faster processer and gpu should be faster, and why is the Gpu used on the PC and not the laptop ?

If I change the format to AVI gpu works on the laptop.

Running windows 10 creators update and the latest Nvidia video drivers and the same Adobe CC version on both.

TIA