Advice for hardware setup to display 11 outputs

[Oaktown]

I think the culprit is your MB and the low memory might very well be VRAM!

I looked at the PCIe specs and here is what it shows:

Slots

• • 2 x PCIe 3.0 x16 slots*
  • 2 x PCIe 3.0 x1 slots
  • 3 x PCI slot

* The PCI_E4 slot will only run PCIe 3.0 x1 speed when the PCI_E1 or PCI_E3 slot is installed a device.

The PCIe lanes are split as folllows as per p29 of attached manual:

E7978v1.0.zip

(2.99 MiB) Downloaded 2380 times

• PCI_E1: PCIe 3.0 x1 slot
  PCI_E3: PCIe 3.0 x1 slot
  PCI_E2: PCIe 3.0 x16 slot
  PCI_E4: PCIe 3.0 x4 slot
  PCI1: PCI slot
  PCI2: PCI slot
  PCI3: PCI slot

So, you only get one x16 speed slot, one x4 speed and then all x1 speed and if you have anything in E1 or E3, then E4 runs at x1 speed so at best you're running at x16, x4, x1 but chances are you're running at x16, x1, x1.

To use three GPUs like what you describe, you'll need an MB that can support at least x16, x8, x8 or even better x16, x16, x16.

My big question is: How did you manage to install 3 GPUs on your MB since the board only has two x16 slots?

[jimberland]

hey oaktown,

thanks for such a detailed response.

i'm working with ellybee on this project and just wanted to update the spec of the MB.

we are actually using this board: ASUS Z170-AR
it has the following expansion slots:
2 x PCIe 3.0/2.0 x16 (x16 or dual x8)
1 x PCIe 3.0/2.0 x16 (max at x4 mode) *1
3 x PCIe 3.0/2.0 x1
1 x PCI

*1: The PCIe x16_3 slot shares bandwidth with SATA6G_56. The PCIe x16_3 is default set at x2 mode.

I believe our IT guy set the 3rd slot to run at x4

so in theory we should be good right?

[Oaktown]

It sounds like you're putting your MB through the ringer.

I believe the Z170 only have 20 PCIE lanes available and from what I could find, here is what your board PCIe lanes look like:

It looks like your PCIEx16_1 and PCIEx16_2 are via CPU whereas your PCIEx16_3 is via Z170 chipset so it's possible that it introduces some instability in your system over the long time.

If you're going to be using 3 GPUs for a long term project, you should definitely get a better MB with 3 PCIEx16 that can run at least at x8 but preferably at x16 AND three matching GPUs.

[Benerman]

Yeah PCI-Express Lanes are important for multi graphics card capabilities. I have done some research and found that the X99 chipset works well with actually having two full x16 speed graphics cards and then for third you can have that at x8 or maybe x16 depending on the CPU and the capabilities of that said CPU.

Do look into this. Especially all those that desire to have multiple graphics cards.

Also prepping a build for 7 Output Machine using at GTX 970 and Blackmagic Decklink Quad 2. Capable of 8 Input/Outputs(Runs at max x4). Excited to see how this performs and its true capabilities.