That card is PCI-X. PCI Express and PCI-X are not compatible, but PCI-X is supposed to be backwards compatible with conventional PCI.
That card *might* (not to be confused with *will*) work, but it would have to go in one of the PCI conventional slots @ a maximum theoretical bandwidth of 133MB/sec (32-bit @ 33MHz). It is intended for 64-bit/133MHz PCI-X, so you would have to check Silicon Image specs to see if the controller is backwards compatible with 32-bit/33MHz (should be but not necessarily).
The DFI board has PCI Express x1 and PCI Express x4 slot, and even a PCI Express x16 if you aren't using SLI, that would offer vastly superior bandwidth. I would look for a PCI Express card instead.