Gigabyte Z97 DH3 Crossfire Performance Question

[Johnnycash]

Hello,

I have had a Gigabyte Z97 DH3 motherboard (http://) in my computer for a little while now, running an R9 290 4GB Graphics card.

The motherboard "officially" states that it is Crossfire compatible. I Know that the board has 1x 3.0 16x PCIE, 1x 2.0 16x PCIE (running at 4x), and 2x PCIE 1x slots.

From what I understand, if I were to Crossfire say, 2x R9 290s, as long as I have the first in the 3.0 16x slot, the 2nd in the 2.0 16x slot, and both 1x slots empty, the two cards would run in 8x/8x configuration. Here is a specification quote from the product page linked above;

1 x PCI Express x16 slot, running at x16 (PCIEX16)
(The PCIEX16 slot conforms to PCI Express 3.0 standard.)
* For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.

1 x PCI Express x16 slot, running at x4 (PCIEX4)
* The PCIEX4 slot shares bandwidth with all PCI Express x1 slots. All PCI Express x1 slots will become unavailable when a PCIe x4 expansion card is installed.
* When installing a x8 or above card in the PCIEX4 slot, make sure to set PCIE Slot Configuration in BIOS Setup to x4. (Refer to Chapter 2, "BIOS Setup," "Peripherals," for more information.)

2 x PCI Express x1 slots
(The PCIEX4 and the PCI Express x1 slots conform to PCI Express 2.0 standard.)

Long question short, is this motherboard really capable of running Crossfire without a (huge) bottleneck on either card? I've done my best to try and understand the topic as best I can, and I'm looking for some community experts who might be able to clarify the issue for me.

Thanks so much for your time

 

[spooky2th]

As long as you have a decent CPU there will not be any bottlenecks. The second X4 PCIe slot will run at max x4 but will not hinder a crossfire setup. And probably will not ever max out anyways. X16 is the max bandwidth and it will be shared by the two slots/R9 290s. The full X16 bandwidth is hardly ever reached even with the most demanding games using high end GPUs. You will see a nice improvement with the two 290's versus just one 290.

 

[real ace]

Yes this board supports crossfire definitely.Unlike Sli in which x8/x8 configuration is necessary radeon cards can do without that.

 

[Johnnycash]

@spooky2th

Thanks for the quick answer! And I'm running an i7 4790K, so bottlenecks will not be an issue from the CPU. I asked this question because Im running an Eyefinity 3 monitor setup and a friend is selling a used R9 290 and I was wondering if it was worth buying.

@real ace

Thanks for the info. I didn't know the whole x8/x8 splitting thing was SLI only. Good to know for future reference!

Much obliged gentlemen.