I have been trying to get an eGPU implementation working on my T450s. The only option I could find for it is through its NGFF slot, which I think is only 1x speed. I picked up the eGPU adapter from yoybuy: http://www.yoybuy.com/en/Show/40808703110.
The graphics card I am testing with is the Zotac 750ti. When plugged into the T450s before boot, the laptop won't post and gives 2 beeps. It does let me chainload, however I can't seem to get the device to show up in the device manager or in Setup 1.30. It's plugged into the port that the wifi chip was in, so it should support more than just SATA right?
Anyways, NGFF eGPU setups seem like uncharted waters, but if anyone has tried this form factor before, please let me know.