Putting 5 PCIe cards on ASUS Z97-PRO: Will they all function at peak?

[danmirage]

Hello,

I am looking at the ASUS Z97-PRO for a research set-up.

My needs would include having four (4) PCIe x1 (PCIe-RTV24) and a video card (EVGA GeForce GTX 970 4GB Superclocked ACX 2.0) I am looking at the PCIe configuration online and I am not certain that they all fit together...

The board has slots, in this order and indicating the corresponding slot position:
1. PCIe x1
2. PCI Express x16 3.0
3. PCIe x1
4. PCIe x1
5. PCI Express x16 3.0
6. PCIe x1
7. PCI Express x16 2.0 (x4 mode)

I presume that the PCIe x1 are 2.0??

I will have the four PCIe x1 cards and the 1 PCI Express x16 3.0 graphics card (two slot spacing, second space BELOW the actual PCI slot occupied).

Sadly, if I put the PCIe x1 cards in place, there is no two slot space near a PCI Express x16.
The alternative is to place the #6 or #3 PCIe x1 into slot #7 (PCI Express x16 2.0 (x4 mode)).

My question is, will this have any impact on the performance of the PCIe x1 in the 2.0 (x4 mode ) slot compared to the other PCIe x1s.

Additionally, I have read “Using the PCIe 2.0 x16 slot in x4 mode disables three of the PCIe 2.0 x1 slots.”
http://www.tested.com/tech/457440-theoretical-vs-actual-bandwidth-pci-express-and-thunderbolt/

Thus, I have concerns if using the PCI Express x16 2.0 (x4 mode) for a PCIe x1 card may have implications for the other PCIe x1 slots.

Proposed build:
Intel Core i7-4790K 4.0GHz Quad-Core Processor
Phanteks PH-TC12DX 68.5 CFM CPU Cooler
Asus Z97-PRO ATX LGA1150 Motherboard
Corsair Vengeance Pro 16GB (2 x 8GB) DDR3-1866 Memory
Sandisk Ultra Plus 256GB 2.5" Solid State Drive
EVGA GeForce GTX 970 4GB Superclocked ACX 2.0 (PCIe x16)
EVGA SuperNOVA NEX 650W 80+ Gold Certified Fully-Modular ATX Power Supply
Microsoft Windows 7 Professional SP1 (64-bit)

Can you advise on this configuration and the fit of the five PCIe cards in the respective slots and the resulting performance?

As a messy alternate solution I have considered employing a PCI-E 1X Card Extender Extension Ribbon/Flex Cable Adapters. That would, however, require some odd modification to get the PCI cards to fit in slots and perhaps multiple card extenders, as they are each about 6" long. I would likely have to put the last PCIe x1 upside down over the PCI Express x16 2.0 (x4 mode) slot.

Thank you for any help you can provide!

Dan

 

[danmirage]

The answer someone should have supplied is NO.

The board has the ports and lanes, but the 1150 socket CPUs only support 16 lanes, some of which are used by other resources, which = bottleneck if I am attempting to use 20 lanes.

1155 socket CPUs appear to also have only 16 lanes of PCIe supported.

Additionally, putting two GPU on there will mean they both utilize 8x instead of 16x in the PCIe on these builds. Plus, they may have to compete for lanes if the max is 16 lanes and you want to use 2x8 or 1x16 lanes.

I am now exploring X79, Sandy Bridge Extreme and socket 2011 because these support PCIe version 3.0 with 40 lanes or more. X79 has 8 additional lanes for onboard so your 40 lanes are dedicated to you GPU and add ons...

There are still rules. You have to use the real x8, x16 to get all lanes and full speeds.

Some ports can compete and some may inactivate other ports, so if you plan multiple PCIe, beyond just 1 or 2 GPU look at the Manual for your board!

Want to explore further? Here is some reading to get your thinking started....
http://www.enthusiastpc.net/articles/00003/1.aspx