Using Laptop as Desktop with External GPU?

I have just brought an Alienware 13 R3 (2017) laptop. My desktop is an ageing 2500K i5 (although it still holds its own well enough) with a GTX 1080. Given how powerful the laptop is I had been considering getting the external GPU dock for my 1080 and using it with the laptop, getting rid of my huge desktop rig in the process.

I have been wanting to upgrade my desktop, but am waiting for the AMD Ryzen to get tested before deciding as the current crop of Intel processors don't seem to offer any major advantage (when I include cost as well) to my 2500K. Will I be able to really extract the power from the 1080 by using the external dock? Going from 16 lanes to just 4 seems to add a bottleneck?