Comment 5 for bug 1834554

Yeah, I considered that and I guess it's a possibility, but if it's the case it's only exercised by the 18.04 X code, this has never appeared prior to the installation of 18.04 a couple of days ago (was previously running 16.04). I don't recall seeing it while running the live usb either, but I can check that when I'm back at the machine.

The other things that makes me feel like it's a software issue is the interdependence of the effect and other activity on the system as mentioned: typing changes the cadence of the updates as does disk i/o; I would not expect that behaviour if it were graphics card RAM failure. It almost feels like someone is writing a buffer in an incorrect location, but the allocation of the screen memory changes with resolution change and this can randomly choose somewhere that's not being abused like that (random stab in the dark).