bus interface?

[froller2]

so well i got my 7970 put in my pci express 3.0 x16 but it only says its x4 in the bus interface, i tried a stress test, rendering and changing from powersaver to max power or whatever it's called, yet it still stands at x4

picture

 

[froller2]

oh my gpu is a saphire hd 7970, and my cpu is a i5 3570k
my motherboard is the asrock pro3 z77