I submitted a run on GCN and in the verification process apparently my gamecube saves faster than the game moderators, what could cause this?

I'm using an elgato hd60 to record gamecube games(via rca to hdmi adapter) and it works fine for like 5 minutes before it starts screen tearing ridiculously, and there's never any temporary stop to the screen tear. It just becomes a ridiculous blur. I was wondering what could be causing this. (Running capture card straight through obs)