I'm hoping for 3 or 4 SMs being put in there, even if it means lowering the clocks to ~800MHz undocked.
Sounds like there is a fan inside the device itself as well, not just the dock. Knowing the Google Pixel C clocks at 850Mhz with an off the shelf Tegra X1 without active cooling, I cant see the clock speed being lower than that in portable mode.