It will be with PCI card. Though I tested with plugging in directly to SATA port using the old IDE power cables we had and it worked. They only problem is we had some customers informing that the HP did not - only with PCI card did it work. So to be safe I would use the PCI card until more inform us that this works with the DELL's.
Many use the External to get it running and they don't mind that the module is outside of the system because they are in locked cages or secured environments.