Z77 Boards With PLX PEX8747

[MacGyverSG1]

I still can't decide which motherboard to get for my i7-3770k. I'm thinking of getting one with a PLX PEX8747 chip for the added PCI-E 3.0 lanes.

My concern though is the added PCI-E 3.0 lanes will only be usable by video cards. I read a review of the ASROCK Z77 Extreme9 and it said if only one video card is used, that PCI-E 3.0 slot gets x16 speed and the other PCI-E 3.0 slots are disabled. I was hoping that the other slots could be used for something else (maybe a PCI-E SSD or RAID card, requiring x8 speed).

I wonder how the ASUS P8Z77 WS or Gigabyte Sniper 3 boards work in this respect. I hope MSI releases a Big Bang XPower for Z77 (and does it right).

 

[MacGyverSG1]

No one has any idea if PCI-E 3.0 slots not used for graphic cards can be used for other devices, with boards using PLX PEX8747 chip? Are the PCI-E 3.0 slots configurable? Say I install a GTX 680 in PCI_E Slot 1 and the rest of the PCI-E 3 slots are free. Can I set PCI_E Slot 1 to be x16 (for GTX 680) and the others to x8 and x8 to be used for PCI-E SSD or RAID card?

I've tried to contact MB manufacturers, but they want MB serial# and other info. I'm not going to buy one until I know how the extra PCI-E 3.0 lanes can be utilized.