Problem with Adobe Illustrator pressure on a Surface pro 7

I recently purchased a Surface Pro 7. I am a graphic designer and an artist and I've always worked on Illustrator but after installing it to my Surface Pro the experience is ruined for me.

I cannot get a sharp line even if my life depended on it. 

Basically the lines inside the box are the lines I'm getting, the single line outside of the box is what I should be getting but I'm not. It's like the pressure works but not on the low end as I can't make a line sharp, it always ends up like this.

By the way - When I first set up my Calligraphic 3x3 pressure brush and when I try to draw a line it looks like it's not being processed but it actually turns out with the right pressure, as it's supposed to be, but then when I get the real time processing (about half a minute later) and I can see the pressure while I am drawing the line I am getting these awful round lines.

P.S. The device is not faulty as the pressure sensitivity works great in Photoshop and Clip Paint Studio and I get great sharp lines there with accurate pressure.

Please help me, I want to continue using Illustrator, that's why I bought the Surface Pro 7 initially, but I just can't get the pressure to work right!