The flickering described is kind of like some of the flicker that occurs with power-lines nearby or other types of external interference
That's why I keep asking if anyone with all metal encased Leadtek 5900 cards have the flicker problem. So far no Leadtek Twin Turbo II all metal encased card user has said anything about flicker, as far as I can see... one person who does have it said they didn't see any flicker. I think its possible that completely metal encased Leadtek (even the fan holes have big metal net mesh covering them) might be immune to the flicker because they are shielded from the outside world?!