Hi and sorry for answering so late,
I tried a lot with the X1 Extreme. I installed a totally fresh system, installed all drivers from Lenovo, disabled optimus and all other stuff not needed - sadly there is no battery to take out... ;-)
I could not get it to work via the startech adapter and the Sonnet box to the Madiface XT.
And I xould not get it to work reliable via USB3 as well.
This is the same problem here:
So I returned the Laptop.
I need a dedicated GPU for my Video work. And yes I, need it at the same time to my Madiface XT via Thunderbolt3 (PCIe).
I setup a lot of Laptops/Desktops for pro Audio work the last 18 years. I tried hard with the X1 Extreme...but there is a limit. I make my money from doing recordings ;-)
Fabian Frank - Arcantus Musikproduktion GbR