PCI-Express port question?

I just got this motherboard

Asrock 775Dual - 880 Pro (Look here!)

and this graphic card

Asus EN7900 GT TOP (Look here!)

The thing im wondering is the motherboard only has a 4 x PCI-E port while the graphic card requires a 16 x.

But in the manual for the motherboard it says that it supports 16 x GFX cards.

How is that possible?

And could it be the reason for this problem i described here?

 

ok i think ive figured it out. the motherboard can support 4x PCI-E by default. however it can support 16x PCI-E, but ONLY certain types. now ive looked at the supported PCI-E gfx card page and ur gfx card isnt supported. so thats means ur gfx card is running at 4x which is probably causing it not to work properly.

 

since the 7900 is a new card, you might want to check for a BIOS update that could allow you to use it.