>>386569139
opt into the steamVR beta and turn on the displayport compatibility/training mode in the steamVR settings, under video or something. scroll down a bit in that window (below resolution settings) and set the mode to A. restart steamVR and see if it works. if not, try B.
this actually worked very well to extend my cable's lifetime and eliminated the green snow and speckles almost entirely for a good couple of months.
make no mistake, the cable still needs replacing. this is just a temporary software solution that's IMO best used while waiting for an RMA or a replacement cable.