I'm thinking 2 things here... and both are related to the bussboard. When you boot does the system find the cards in early startup? and after a softreset? What I'm thinking is either bad bussboard or low power.
Suggestions: Check that all powercables are connected correctly (reseat them) and remove all other hardware from the bussboard and see if it helps (could be both hardware that doesn't like eachother or low power). Last thing try the Zorrocards in a different system to see if they work there.
