GA-X79-UD7 / UD5: Confirm x16-x8-x16 3-way link?

[eduncan911]

Can someone confirm that the Gigabyte GA-X79-UD7 or GA-X79-UD5 supports the following link speeds with 3-way cards?

x16 - x16 - x8

Getting conflicting information from NewEgg (saying x16 - x8 -x16 -x8), which we know isn't possible on the X79 chipset. 

Looking at manual:

http://download.gigabyte.us/FileList/Manual/mb_manual_ga-x79-ud7_e.pdf

It has a component map that clearly shows at 1 slot dedicated at x16 at all times.  The other x16 is "switchable".  Down in the manual on page 10, it says:

The PCIEX8_2 slot shares bandwidth with the PCIEX16_2 slot. When the PCIEX8_2
slot is populated, the PCIEX16_2 slot will operate at up to x8 mode.

Ok, that makes sense.  PCIEX8_2 is the "4th" slot FYI.  So, when the 4th slot is populated, it sounds like it drops PCIEX16_2 (the 3rd slot in teh system) down to x8 for a total of x16-x8-x8-x8.  That makes absolute perfect sense.


But behold, then I read this in the manual, just a couple of lines down on the same page:

Support for 4-Way/3-Way/2-Way AMD CrossFireX™/NVIDIA SLI technology
*   The PCIEX16 slots operate at up to x8 mode when 4-Way/3-Way  AMD
CrossFireX™/NVIDIA SLI is enabled.

Whaaa?  Now we are at x8-x8-x8-x8 in 4-way, and 3-way modes? 


Please, can someone with 3-way SLI or Crossfire confirm the link speeds on the UD7 or the UD5?

[Gloup_Gloup]

Hi eduncan911,

Welcome to forum,

Well, I see in manual of GA-X79-UD7 (rev. 1.0) :

Expansion Slots   

    2 x PCI Express x16 slots, running at x16 (PCIEX16_1, PCIEX16_2)
    * For optimum performance, if only one PCI Express graphics card is to be installed, be sure to install it in the PCIEX16 slot.
  
     2 x PCI Express x16 slot, running at x8 (PCIEX8_1, PCIEX8_2)
    * The PCIEX8_2 slot shares bandwidth with the PCIEX16_2 slot.
       When the PCIEX8_2 slot is populated, the PCIEX16_2 slot will operate at up to x8 mode.
    (All PCI Express x16 slots conform to PCI Express 3.0 standard.)

    3 x PCI Express x1 slots
    (All PCI Express x1 slots conform to PCI Express 2.0 standard.)

As I see no information to the effect that ''When the slot PCIEX8_1 is populated, the slot PCIEX16_1 will operate at up to x8 mode''
I understand that there may be three (3) graphics cards to run in link speeds with 3-way cards.

I add a picture...

Gloup_Gloup

[Dark Mantis]

I would agree there from the information I have to hand that the maximum attainable is 16x, 8x, 16x or 16x, 8x, 8x, 8x

[Gloup_Gloup]

Hi Dark Mantis, 

Thanks a lot...

Pfiew   my english is not perfect, but I understands more than before past time....

Against sometimes I find this difficult enough to understand the message on the topic.

Gloup_Gloup

[Dark Mantis]

I think you manage very well on most posts. There are some posts that even I have trouble making sense of so I wouldn't worry about it. 

[Gloup_Gloup]

I think you manage very well on most posts. There are some posts that even I have trouble making sense of so I wouldn't worry about it. 

Hi Dark Mantis, 

I see this as a compliment.

And for you, as a surpassing oneself.

Gloup_Gloup