Xrott

Just guessing, but it sounds like a bad/loose connection between some cables. Maybe some dust gathered inside your ports or there has been some corrosion on the pins? To test that you could wiggle your cables around at the connectors and whenever it's at a spot where it's working right, try holding them in place and see if the problem stops.

Glad I could help!

This looks suspiciously like anti-aliasing. Either the image is offset by like 0.5 pixels or there is a edge-smoothing function enabled. Try adding a offset of 0.5 yourself and see if that fixes it. EDIT: actually it looks like it's only offset on the y-axis