I noticed it goes jerky with 'very' slow movements. Here's the pic:

i.imgur.com/cQ0U2jD.png

I don't know if it's always been like this or not, I only started investigating after I saw a few other jitter posts.

450dpi, 500hz. Razer goliathus speed.

UPDATE:

I think I might have fixed it?

i.imgur.com/0ZpYQKN.png

I battered the crap out of the mouse mat to try and get any dust off it, then I took a cotton bud, stuck it in the hole and gave it a really good few twists against the lens. Now the small movements seem ok.

There seemed to be a lot of black stuff on the cotton bud afterwards. I wonder if this could solve other peoples abyssus jitter problems?