I've been using AP for about 2 years and I've never had a single problem until I updated to 1.7 where there's a very noticeable pixelated look in everything (text, pen tool, shapes, etc) and I also seem to have this line using gradients found also in the linked post. Do keep in mind though that I got a new PC around the same time as 1.7 so it could also be that but I'm unsure. I've posted my settings and an example. I'm not sure whether this is the correct place to ask this or not so please correct me if I'm wrong.