Question Can you connect 2 GPUs without a physical link (NVlink) through PCIe?

[manute771]

Mother board: ROG STRIX Z790-E GAMING WIFI
Video Cards: NVIDIA GeForce RTX 4070

Hi,

I am trying to run a program that is able to use multiple GPUs to scale its efficiency. When I try to run the program, it says that my GPUs are not paired. My video cards are not compatible with NVLink or any physical bridge. +

However, I thought that you could establish a connection between the PCIe slots where the cards are installed (albeit it would not be as fast as a physical connection).

Is this possible?

Thanks!

Chad

 

[Lutfij]

Simple answer, no.

When I try to run the program, it says that my GPUs are not paired. My video cards are not compatible with NVLink or any physical bridge. +
Nvidia did away with SLI.

 

[Eximo]

Simple answer, yes. You don't need an SLI bridge/NVLink for a lot of non gaming tasks.

However, they do need to be connected to the same PCIe bus, and Nvidia in particular requires 8x connections for a lot of functions. That motherboard's second PCIe slot is connected to the chipset at 4x, not the CPU.

Intel14th & 13th & 12th Gen Processors
1 x PCIe 5.0 x16 slot

Intel Z790 Chipset
2 x PCIe 4.0 x16 slots (support x4 mode)

So you would have to swap boards for one that can do 8x/8x.

Simpler solution is to get yourself a single larger GPU, and sell those 4070 before the 50 series launches.

 

[manute771]

Simple answer, yes. You don't need an SLI bridge/NVLink for a lot of non gaming tasks.

However, they do need to be connected to the same PCIe bus, and Nvidia in particular requires 8x connections for a lot of functions. That motherboard's second PCIe slot is connected to the chipset at 4x, not the CPU.

Intel14th & 13th & 12th Gen Processors
1 x PCIe 5.0 x16 slot

Intel Z790 Chipset
2 x PCIe 4.0 x16 slots (support x4 mode)

So you would have to swap boards for one that can do 8x/8x.

Simpler solution is to get yourself a single larger GPU, and sell those 4070 before the 50 series launches.

Thank you for the information. Sorry if this is an ignorant question but my board seems to have 3 PCIEX16 slots - specifically labeled PCIEX16(G5), PCIEX16(G4)_1, and PCIEX16(G4)_2. Does that make any difference?

I tried to upload an image of the schematics of my board but it didn't work. Below is a link to a PDF of the manual.

Thank you again for the information. I have been trying to figure this out for two days now.

PDF of Manual

 

[Zerk2012]

Thank you for the information. Sorry if this is an ignorant question but my board seems to have 3 PCIEX16 slots - specifically labeled PCIEX16(G5), PCIEX16(G4)_1, and PCIEX16(G4)_2. Does that make any difference?

I tried to upload an image of the schematics of my board but it didn't work. Below is a link to a PDF of the manual.

Thank you again for the information. I have been trying to figure this out for two days now.

PDF of Manual

Intel^® 14th & 13th & 12th Gen Processors
1 x PCIe 5.0 x16 slot

Intel^® Z790 Chipset
2 x PCIe 4.0 x16 slots (support x4 mode

ROG STRIX Z790-E GAMING WIFI | Motherboards | ROG United States

The ROG Strix Z790-E Gaming WiFi supercharges builds with its robust 18-stage power solution, hyperspeed DDR5 memory, and next-gen PCIe 5.0 connectivity. It features five M.2 SSD slots with heatsinks, USB 3.2 Gen 2x2 support, WiFi 6E, AI Overclocking, AI Cooling II, AI Networking, Two-Way AI...

rog.asus.com

X16 is just a form factor.

 

[kanewolf]

Simple answer, yes. You don't need an SLI bridge/NVLink for a lot of non gaming tasks.

However, they do need to be connected to the same PCIe bus, and Nvidia in particular requires 8x connections for a lot of functions. That motherboard's second PCIe slot is connected to the chipset at 4x, not the CPU.

Intel14th & 13th & 12th Gen Processors
1 x PCIe 5.0 x16 slot

Intel Z790 Chipset
2 x PCIe 4.0 x16 slots (support x4 mode)

So you would have to swap boards for one that can do 8x/8x.

Simpler solution is to get yourself a single larger GPU, and sell those 4070 before the 50 series launches.

AND just because it is possible, that does not directly imply that whatever software the OP is using supports that configuration. It requires software and hardware.

 

[Eximo]

Thank you for the information. Sorry if this is an ignorant question but my board seems to have 3 PCIEX16 slots - specifically labeled PCIEX16(G5), PCIEX16(G4)_1, and PCIEX16(G4)_2. Does that make any difference?

I tried to upload an image of the schematics of my board but it didn't work. Below is a link to a PDF of the manual.

Thank you again for the information. I have been trying to figure this out for two days now.

PDF of Manual

I did look at the board before answering. Your 2nd and 3rd PCIe slots aren't intended for graphics cards.

As Kanewolf pointed out, even if you can get the cards to share a PCIe bus, that doesn't mean your software will work with it.

The point of SLI/NVlink was to provide a direct connection between the memory buffers of each card so that they would have identical information between them. This also means that your total available VRAM is the same as a single card.

Multiple GPU for things like rendering doesn't require any particular connection. If this is some sort of real time rendering, then it likely won't work without true SLI. Even motherboards with dual 8x slots don't necessarily support SLI, it has to be specifically enabled and licensed by Nvidia.

If you name the application, a more direct answer is possible.