Thank you! This solved is a work-around for me.
I have 200 Mbps connection on a Fiber optic connect, and 5 GHz Wifi network at home. Less capable laptops and also smartphones on the network could download at full 200 Mbps while my new Surface Book 2 13 inch maxed out at ~120 Mbps on the same connection.
By changing the adapter setting to only use 5 GHz, this problem was solved. I now also get full download speed!
Microsoft should really look into this! These are very expensive devices and thus should simply
work.
Because while this helps me at home, now when i'm trying to connect somewhere else, I will probably need to manually switch to auto or 2.4 GHz when on the road.
**Update:**After restart the speed caps at ~120 Mbps again. And the only way to get it to have high download speeds once more is to switch between
any of the modes found under: Device Manager > Marvel AVASTAR .... > Advanced > Band.
So it seems that the setting itself doesn't matter (in my case), but when switching modes something happens that allows the speed to go up temporarily.
Still waiting for a fix Microsoft!