Gigabyte GA-MA790X-UD3P AMD 790X Crossfire pcie running at 8x

[GhostyUK]

Hi ive just built this pc with a Gigabyte GA-MA790X-UD3P AMD 790X mother board and decided to install two hd 5770 cards in it for crossfire. The problem im having is the cards are only running at x8 speed.

When i use GPU-Z it reports that the card supports pci-e 2.0 x16 @ x8

ill post a screenshot, is there anything i need to setup in the bios because this board says on the specs that it has two times x16 pcie 2.0 ports ?

any help please.

 

[RJC]

In crossfire mode the ports run at 8x.
The second slot utilises bandwidth from the first slot.

(edit your sig is to big, max 400 x 75 )

 

[GhostyUK]

In crossfire mode the ports run at 8x.
The second slot utilises bandwidth from the first slot.

(edit your sig is to big, max 400 x 75 )

ok thanks for clearing that up for me.

 

[thingemajib]

yeah, for two 5770s, it wont impact on performance. 8x will provide enough bandwidth.
if you desperately want both slots running at 16x, then you want a motherboard with a 790fx/890fx, not 790x.

 

[GhostyUK]

yeah, for two 5770s, it wont impact on performance. 8x will provide enough bandwidth.
if you desperately want both slots running at 16x, then you want a motherboard with a 790fx/890fx, not 790x.

I dont see much of an improvement with two cards rather than one to be honest. Ive also noticed on gpu-z that the second card has less shaders than the first, ill post pictures below.

One card has 800 shaders and the other has 720

im using the corsair 650w psu will that be alright for two of these cards ?

Sapphire ATI Radeon HD 5770 Vapor-X 1024MB GDDR5 PCI-Express Graphics Card

Card 1

Card 2