Different choices for first and second M.2

[PhilHibbs]

Quite a few of the laptops have a bigger choice for the first M.2 drive than for the second. Why is this, do they have different slots?

For example, the Defiance IX 17.3" can have a PCS drive in the first slot but not the second. It can't have a Samsung 980 PRO in either.

The Recoil V 17.2" can have a Samsung 980 PRO in the first, but not in the others. It can have a PCS stick in all slots though.

Are these just at whim to cut down the number of options for simplicity, or is there a technical reason why I can't have two 980 PRO sticks?

 

[Scott]

It's down to the limitation of the PCI lanes of the ports. The first port with 980 availability will be with a gen 4 port. The second port will be gen 3, hence limited options. The first laptop you mention will likely have a gen 3 primary port with a limited speed secondary port, possibly Sata.

You can fit the 980 in any of the laptops but it will be limited by the speed of the interface, hence why it's not offered as this could be seen as performing poorly compared to spec.