Nicholas is right, with pci-e x4.3 you lose about 5% in comparsion to a full x16.3 slot on a GTX 980 TI. Proof: https://www.techpowerup.com/reviews/NVIDIA…

Gnarkiller is right on this one, if you visit the tech-inferno
forums you’ll see that the principle is the same.
With TB2 you could already use a AkiTiO Thunder2 Box.
Depending on your system, just plug it in and you have a Desktop GPU.

because 4K in a gaming laptop is hilariously pointless