Motherboard + Crossfire

[morrowmedia]

I have an Gigabyte P55A-UD3 (ver. 1) It has 2 PCIe slots, 1 is x16 and the other is x4. If I run 2 HD5770's in Crossfire am I going to see a jump in FPS/Performance? Or would I be better off finding a mother board that has 2 PCIe x16 slots? I'm very new to crossfire/Sli, last computer I had in SLI had 2 VooDoo 2 from 3dfx.

Thanks,

Zach

 

[Fumz]

16x4x Crossfire doesn't perform as well as 8x8x and is nowhere near 16x16x. However, two 5770's would not saturate an 8x8x lane. Unfortunately, you've got a 4x slot. Best advice: get a faster card or a board that supports at least 8x8x. 16x16x you could not make use of given two 5770s.

Putting current graphics cards in a PCI-Express x4 slot basically verges on madness and incurs a performance hit of between 25 and 33 percent. Even if the motherboard in question were especially cheap, the card’s price/performance ratio is affected immensely. When using an x8 connection, performance also decreases, albeit only by 7 to 8 percent.

From the conclusion.
Crossfire meets PCI Express 2.0 – More Lanes, More Frames? : Crossfire up to 20 Percent Faster

 

[morrowmedia]

Would this board be good?

 

[Fumz]

Oh yeah. Gigabyte has been coming out with some impressive stuff lately. Their ultra durable products are top notch.

 

[morrowmedia]

I have the GIGABYTE GA-P55A-UD3, so I wonder if I can just swap motherboards and not have to change crap on the OS install to use it...Would this board allow me to run at PCIe x 8 on both cards?

 

[Fumz]

Yes, you can run at 8x8x. No, you will not have to reinstall the OS.