I think the issue is anti-aliasing, you want it turned on. Go to System Options > Display/Selection > Anti-aliasing and set it to edges/sketches or full scene.
Go here and enter your system information and see if you are using the recommended graphics card driver.
Graphics Card Drivers | SOLIDWORKS
If you already are, then maybe your graphics card doesn't support anti-aliasing.
Actually, I don't know about AMD but the nVidia control panel has options where I guess you can override the anti-aliasing settings. If AMD has something similar try to set everything to application-controlled.
Change image quality to reduce these under Tools > Options > Document Property > Image Quality (move slider to right)