Topic: PCIe RayDAT Question: MacPro Slot order?

I'm usng a MacPro 8Core (late 2009) with a RayDAT PCIe Card.
Beside the RayDat i've 2 grafik cards (DVI) on the mainboard.
Is there any specific order how pci cards should be arranged?

Since i've recently started to use the RayDAT not only for out-
put, i'm getting DC offsets at about -70dB on both channels
which are not coming from the source audio. Even without
any cables this kind of signal is in the digital input. There is
something going on and i want to make shure the setup of
cards is in the right order. Is the PCI bus getting "distortion"
from other busses etc? The grafic cards are not of the same
sort and speed. Any info could be helpful

Thanks. Floflood