Sign in with
Sign up | Sign in
Your question
Solved

Can dual PCI-e Gen3 @ x16 on Asrock Z97 Extreme9 be real?

Tags:
  • Motherboards
  • Graphics Cards
  • ASrock
  • Dual
  • PCI Express
Last response: in Motherboards
Share
October 8, 2014 4:17:20 PM

Searching on newegg.com found that this board:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

said: "4 x PCI Express 3.0 x16 Slots (PCIE1/PCIE2/PCIE4/PCIE5: single at x16 (PCIE1); dual at x16 (PCIE1) / x16 (PCIE4); triple at x8 (PCIE1) / x8 (PCIE2) / x16 (PCIE4); quad at x8 (PCIE1) / x8 (PCIE2) / x8 (PCIE4) / x8 (PCIE5))".

More clearly, PCI-e configuration: single at x16; dual at x16/x16; triple at x8/x8/x16; quad at x8/x8x8/x8.

How a 16 lane CPU can handle two graphics at x16 each one? Is this info correct?

I also found same specs on manufacturer's website:

http://www.asrock.com/mb/Intel/Z97%20Extreme9/?cat=Spec...

Thanks for reading :) 

More about : dual pci gen3 x16 asrock z97 extreme9 real

Best solution

a b V Motherboard
a b U Graphics card
October 8, 2014 4:28:24 PM

A fairly basic answer:

It uses a PLX 8747 PCI-E switch chip which manages the distribution of those 16 lanes into two split 16 lanes, so each 2 slots share bandwidth with each other (8x each), and the switch manages the data link between CPU and the devices to make that all fit in the 16 lanes to the CPU.

Maybe someone else can provide a more technically detailed description, but this should help you get the gist of things. It's basically a necessary component to allow 3-4 way SLI on z97 motherboards. I have one such board, the Gigabyte Z97X-Gaming GT. It really does work well, I've run 3-way 780s with a 750Ti pulling PhysX duty and I've yet to encounter any problems.
Share
a b V Motherboard
a b U Graphics card
October 8, 2014 4:35:13 PM

Why do you think it is a 16 lane CPU?

As far as I know/understand the PCIe lanes go between the northbridge and the physical PCIe slots. The connection between the CPU and northbridge is a completely different configuration (and depends on the CPU/chipset/architecture)

Edit: Also the number of available lanes is dependant on the chipset. for example:
•The AMD 990FX, 890FX and 790FX chipsets have support for a total of 42 PCI Express lanes.
•The AMD 880G, 870, 790GX, 785G chipsets have support for a total of 22 PCI Express lanes.
m
0
l
a c 95 V Motherboard
a b U Graphics card
October 8, 2014 5:09:36 PM

Current intel 1150/1155 processors support 16 pcie lanes natively. They dont get routed thru the chipset.
m
1
l
October 8, 2014 5:11:58 PM

menetlaus said:
Why do you think it is a 16 lane CPU?

As far as I know/understand the PCIe lanes go between the northbridge and the physical PCIe slots. The connection between the CPU and northbridge is a completely different configuration (and depends on the CPU/chipset/architecture)

Edit: Also the number of available lanes is dependant on the chipset. for example:
•The AMD 990FX, 890FX and 790FX chipsets have support for a total of 42 PCI Express lanes.
•The AMD 880G, 870, 790GX, 785G chipsets have support for a total of 22 PCI Express lanes.


Maybe on AMD. I got Intel Core i5 4570 and the specs are 16 PCI-e lanes on the CPU.

m
0
l
October 8, 2014 5:23:50 PM

popatim said:
Current intel 1150/1155 processors support 16 pcie lanes natively. They dont get routed thru the chipset.


So two graphics cards will really work at PCI-e Gen3 x8/x8 and not at x16/x16?
m
0
l
a c 95 V Motherboard
a b U Graphics card
October 8, 2014 5:47:07 PM

As mentioned, that board uses a special chip to multiplex the lanes. Toms reviewed a similar chip a few years ago and found the impact on performance was minimal.

Without the special chip, Intel natively supports single X16, X8/X8, or X8/X4/X4 depending on how the motherbd manufacturer decides to implement it.

m
1
l
!