First time build, question about mb/ video card compatibility

Hello,
I just ordered parts for a build on Amazon about 4 days ago. Everything is here except the case, so I have not opened anything or done anything yet.

Anyways, I got this motherboard:
Gigabyte P67A-D3-B3 DDR3 2133 LGA 1155 Intel P67 SATA 6Gb/s USB 3.0 ATX Intel Motherboard

and this card:
HIS Radeon HD 6950 IceQ X Turbo 2GB (256bit) GDDR5 2x Mini-DisplayPort HDMI 2x DVI (HDCP) PCIe X16 2.1 Video Card H695QNT2G2M

Upon looking closely at the boxes, the Graphics card states that it requires one PCI Express X16 slot, with 2 slots available. The motherboard has one X16 slot. Am I misreading this, or why would I need one slot but need to have two available? Is it the size of the card? Do I need a different mb?

EDIT/ UPDATE:
Well, Looking at the picture on the box closely it actually looks like my mb does have 2 x16 slots, even though it claims it only has one. Unless I'm completely misunderstanding but I looked up what the slot looks like and it looks like I've got two. Also found a reviewer on Amazon using this card who is using a mb that has one x16 slot... still I'd like to know why this card says it needs "2 slots space available on the motherboard".

Thank you for any help.