Jagged Edges when Rendering with Brazil for Rhino

Does anyone know why I get jagged edges when I increase the image size (pixels) and render the image? The image looks fine when I do like 640x480, but if I increase to 2000x2000 the edges of the 3D model start becoming jagged. I’m wondering if there are any settings I can change that anyone can help me out with. I use Rhino 6 with Brazil Render. Laptop: Lenovo P52