[Solved] Huawei Matebook X Pro - 2 PCIe Lanes for Thunderbolt 3 Port  

It's almost certainly an x2 in the discrete configuration (core 8*50U chip + MX150 => x2). There is a chance it's a x4 in the non-discrete variant, but they don't have a separate spec page (the giveaway would be if that variant is also USB-C + TB3, or TB3 + TB3 - like the difference between the 13" and the 15" Spectre x360).

Alright thanks for the answer. I guess I'll wait till someone gets their hands on the device.

Notebookcheck's review of the laptop (which included the MX150) states it's a 4-lane implementation, but I know thats not conclusive.

@usafballer I read notebookcheck's review of this laptop (i5-8250U, MX150) and while they listed full 4 lanes TB3 as a pros I did not find any factual screen captures or performance tests. The NVMe results indicate there are 4 lanes to the M.2 slot. The MX150 dGPU needs 4 lanes. I highly doubt the Thunderbolt 3 controller gets the remaining 4 lanes. Like @4chip4 said, it's most likely a x2 PCIe connection with one Thunderbolt 3 port.

I agree with you @itsage - it's likely 2 lanes, which is a bummer.  I am contacting support to ask - first response they said "yes it features 2 USB-C ports".  Waiting on one more follow up.  Still one hell of a great laptop deal with a unique screen ratio for under 1200 bucks.  And 2 lanes is still fine if you are outputting to external monitor only with only a minor loss in performance.

I am sure that they are just PCIe x 2 Lan.

Both Huawei support and an amazon user have confirmed it is only 2-lanes.

I am currently in contact with Huawei themselfs as I am too getting contradicting statements about this, I will keep you posted once I find something out,

I got a question myself thou, I saw today a report of someone hinting to issues in setting up a system with an eGPU and the MateBook Xpro, does anyone know why that should be? Is anyone of you running this setup or anything similar with a matebook?

@usafballer were you able to confirm this for certain? As seemingly the customer support has no idea and is just giving the next best answer, I am by now taling to the engineering team.

The single Thunderbolt 3 port is attached to a 2-lane PCI Express Root [Port #9]. Confirmed here by u/Shirokiya on reddit. We can see the dGPU uses 4 lanes [Port #1], NVMe drive uses 4 lanes [Port #5], and my guess is the wireless card uses at least 1 lane [Port #11].