The physical design of this slot is similar to PCI Express x1 but turned by 180 degrees, however there is no electrical compatibility with the PCI Express x1. The thing is that Supreme-FX is actually not a fully-fledged sound card, but simply an analogue part of the sound tract connected to the AC97 interface. That is why you can only see a one microchip on the Supreme-FX card: the high-definition 8-channel Analog Devices AD1988B codec