Foxconn Leak was real, when Docked Switch is about 70 % Xbone

[FunFan]

SmileyAja said:

The Traktor speculation about the additional docks with GPUs is impossible, all external GPU docks you see around use Thunderbolt 3, which is based off USB-C but is improved and faster, it's 40gbps compared to 10gbps, and the Switch won't be using Thunderbolt, IIRC the nVidia tech isn't compatible with Thunderbolt anyways, so that's a no go.

Now OP's in the ballpark but he doesn't specify his calculations, here's one on Reddit that does a better job of explaining this type of performance;

https://www.reddit.com/r/NintendoSwitch/comments/5jlbub/clock_speeds_power_efficiency_and_why_the/

We'll probably be seeing closer 750 GFLOPS though (as the P1 can do that max), but time will tell. This is using a die shrink of Maxwell and not full on Pascal for a "worst" case scenario.

It has been done: http://www.anandtech.com/show/9963/asus-booth-tour-at-ces-2016-10g-switches-external-gpu-dock-usb-c/2