For what reason do I need the PCI-E(x4) slot?

Hello,

I bought a motherboard originally to try CrossFireX on it. However it seems that the motherboard, although supporting HybridCrossFireX on both the PCI-Ex16 and the PCI-Ex4 slots, it does not allow CrossFireX configuration between two cards. The motherboard in question is the GA-MA785GT-UD3H just in case you think of buying it for the same reasons as mine.

Anyways, I have a good setup so I have no reason to panic. However this episode made me wonder; for what else would I need to additional PCI-Ex4 slot? This for me does not make sense either in a HybridCrossFireX configuration since HybridCrossFireX only works between the the IGP and one GPU or else the IGP and two GPUs as long as the second PCI-E slot is x8 (from wikipedia).

For me it feels that the second PCI-Ex4 slot on this motherboard is useless. Even more useless to have this slot support HybridCrossFireX. However I am no hardware expert and would like to know what else I can put in this slot just out of curiosity.

The motherboard has on-board sound card so I wouldn't need that either, neither a network card (also on-board). I have several USB slots as well so no reason for that either.

You could place a eSata card in it.

I know there are x1 port, but depending at the size of the graphic card, this will give some air space between the the two cards.

You could use the x4 for some SSD action and put Windows on the SSD to improve performance...