Display flickering even in console mode

Whilst in Windows things work fine, in Ubuntu the screen flickers every few seconds. To describe the flicker, the entire display appears to jump up and down by a single pixel.

This happens even if I boot into console mode (by using sudo systemctl set-default multi-user.target ) so I am not sure if this means display drivers can be discounted (as they are not loaded at that point).

Laptop is Razer Blade 15" (2021) running Ubuntu 21.04. The graphics card is GeForce RTX 3070. The screen resolution is 1920x1080 running at 60Hz (the laptop can do 360Hz but only with Nvidia drivers).

Any ideas?