Din cate vad acolo ai asa:

1 x PCI Express x16 slot, running at x16
(The PCI Express x16 slot conforms to PCI Express 3.0 standard.)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.

1 x PCI Express x16 slot, running at x4 (PCIEX4)

2 x PCI Express x1 slots
(PCIEX4 and PCIEX1 slots conform to PCI Express 2.0 standard.)

2 x PCI slots

Prin urmare, ai un singur slot PCI Express x16, si care e 3.0. Acolo poti folosi orice fel de placa video, in single mode la performanta maxima.
Mai ai un slot x16, dar care odata populat va merge doar in x4... si aproape sigur iti va trece si primul slot in x8 (nu vad niciun PLL pe placa).
In concluzie, mai repede iei o placa video mai rapida si o pui in slotul 1 PCIE, decat 2 care sa mearga limitate.