When I open a new tab in Safari sometimes my screen goes crazy, anyone one else?

I am running the latest version of Safari on snow Leopard. Sometimes(usually when I first open Safari or have not used it for awhile) when I open a new tab the screen will get crazy like all video garbage then fix itself after 2–3 seconds. This only happens with Safari. Does this mean my video card is going bad? I don’t think so since it is only Safari that I have ever seen anything like this happen with.