If the screenshot KaMo posted tells the truth, SketchUp is using the Nvidia
You should definitely try changing the settings for SketchUp to always use the Nvidia card. Auto select might lead to Windows switching to integrated graphics randomly - for instance if you are running your laptop on the battery instead of always plugged in.
regardless of this do what @Anssi told you and explicitly configure in the nVidia 3D control panel that SU uses the GeForce⦠otherwise the next W10 update might do a fallback to the lame intel HD again.
many intel graphics cards just donāt support multi sampling at all. turn off multisample in Window-preferences-OpenGL. also if you use hybrid GPUs force the other(more powerful) graphics card.