I've installed ubuntu 19.10 on Lenovo Yoga S940 and it has some problems with refreshing the screen where it leaves multiple cursor traces when you move it, it doesn't redraw the input when you type something and similar stuff, so overall it creates a "laggish" impression (same on the preinstalled Windows btw, but this can be fixed there with some settings in the intel app).
What I've noticed is that when I boot from LifeUSB in safe graphics mode, everything works just perfect (well, except poweroff and suspension problems).
Seems like some graphic driver setting might cause the problem.
There are a lot of suggestions out there for similar problem but none of them worked for me so far and I'm wondering if anyone experienced this problem on this particular (or similar) configuration and might now a possible fix?