I have a Surface Book 1 and I'm having similar performance issues. It's *incredibly* frustrating to spend tons of money on this computer and have performance issues. This is a Microsoft-built computer running Microsoft Windows! You'd think Microsoft would make absolutely sure that their own OS would run flawlessly on their flagship computer. But, no. Honestly, this will keep me from recommending a Surface Book to anyone who asks. I love the hardware, but the quirky performance issues are a real drag. And the bugs...my god Microsoft, I'm uncovering new bugs with Windows 10 almost weekly. And once Windows 10 seems OKish, Microsoft issues a new OS version with new bugs. Then they come out with cumulative patches that are nothing but quality "improvements" to fix bugs. Not sure what's going on with testing at Microsoft, but it's frustrating.
That being said, my workaround to the UI issues has been to disable most Window visual effects:
1. Hit Window key + R.
2. Enter sysdm.cpl.
3. Go to Performance.
4, I selected "Adjust for best performance" and then added a few features back in. Seems like getting rid of all of the "animations" and "fades" has improved things dramatically.
I still have my resolution at max (3000x2000 for Surface Book). There are some minor lags, but it's much better. Knocking down my resolution does the trick too but the screen's not nearly as clear when I do that. I prefer running full resolution with minimal visual effects.