TerraTec Cinergy T PCIe dual freezes the system

Hello everybody,
I want to use 2 TerraTec Cinergy T PCIe dual PCIe-cards in the same system. Both cards are working without any problems if used standalone. If both cards are used parallel the hole system freezes mostly on loading the kernel modules. There are no error messages in the log files. Sometimes (very seldom) the modules are loaded successfully and then both cards can work over hours without problems. Freezing occurs before starting a dvb application.Maybe someone has an idea what to do.