We've had a stack of recurring questions from with problems getting a mPCIe eGPU working. This includes GPU-Z not reporting no clock details, error 10/43 or even not being detected at all. Overall it's more troublesome getting mPCIe working than say expresscard or Thunderbolt.
Here's some common problems and some troubleshooting steps to correct them.
Getting a black bootup screen, resolving error 10/43 or ACPI_BIOS_ERROR win bootup messages
Here the BIOS does