Toolpath smoothness of circles

When I’m running a job that includes holes, the axes movement if not smooth. The holes come out quite alright but the machine is shaking heavily when running at a high feed rate.

Taking a closer look to the toolpath, it seems that Easel simplifies the circle and creates very few coordinates of the circle. I’m routing 16 mm holes using a 6 mm bit, so especially the inner circle operations are anything but smooth.

Please have a look at the toolpath simulations below. What would be a good number of coordinates to break up a circle this size? Is there a way to increase resolution of the toolpath in Easel? Or would this resolution be different in other CAM software?

btw. I’m generating the G-Code in Easel, then export it and run via Mach3 to a very stable CNC with ball-screws etc. (so its not about belt tension, pulleys etc).
Thanks already for your suggestions