I couldn't find GTX890M, so are you talking about 880 or 860? In either case the video card is on the weak side for AH3. Based on PassMark benchmarks it's at the same level as Radeon HD6970 and GeForce GTX 750Ti which should provide a playable performance at 1920x1080, 60Hz. However, you're using a 4K monitor which means 4 times the load of a 1080p! You could try scaling the game resolution down to 1080p, that should help.
Another potential issue is that your computer, assuming it's a laptop because of the "M" in the GPU, has reset the graphics settings to use the basic video instead of the Nvidia. It can happen when you update the drivers. Go to the Nvidia control panel, 3D settings, Program settings tab and check that AH3 uses the Nvidia GPU.