picture on tv screen jumping up and down (pulsing)

[obiwan]

i have a problem where tmnt and the Simpson's games moves up and down (pulse)on the screen about an inch ,it is running on a sanyo 25 inch TV from a ati card.

my PC Pentium 3 500 MHz,256 ram,20 GB hd.
any idea?

[gearguy]

That really sounds like the V. Sync and your monitor aren't agreeing with each other there.
I can't think of any other reason for a picture to jump up and down (and it's probable not no RGB switching since that would cause it to roll diagonally).

[obiwan]

but if that was the case wouldn't it do it in all games and not just a few ,also when playing galaga it chops off the lower portion of the screen where the ship is! im thinking this is a rom problem?