Photoshop :: Lineart Looks Pixelated

I've been using Photoshop CS5 for years now and never had any trouble with my lineart. I use an Intuos 4 tablet. This is what my lines used to look like last time I used Photoshop. Always on a 1 px round brush with the following settings:

Now, all of a sudden, my lineart looks pixelated. I am using the exact same settings and even tried updating my drivers, it has not been fixed. It's causing me insane amounts of stress since this is what I do for a living and the decrease in lineart quality is really taking a hit on my work.This is what they look like now..