Yet Another Hardware Question PCIe Requirements

When NOT being used as a graphics output card what is the MINIMUM number of PCIe channels required to function as a GPGPU device:

A. For G80 cards;

B. For single G92 cards with a version 1 PCIe slot;

C. For single G92 cards with a version 2 PCIe slot;

D. For dual G92 cards with a version 1 PCIe slot;

E. For dual G92 cards with a version 2 PCIe slot?

Since the G80 cards do not support PCIe 2.0 I assume that the version of the slot has no influence on the number of channels required. Thanks for any input or reference to documentation on this question.

Skippy

Although I would still like to know the answers to my questions in my original post, the question I really need an answer to is:

Will a 9800GX2 function in a PCIe x16 version 1 slot with EIGHT channels?

Skippy

If you know, please add if answer is from first hand knowledge, documentation or speculation. Thanks.

I’m not sure what exactly you mean by PCIe channels. All our GPUs work best with PCIe x16 connections.

I believe they will function in slots with fewer lanes, but the data transfer rates will be reduced accordingly.

Sorry if my sloppy terminology was confusing. I will rephrase:

When NOT being used as a graphics output card what is the MINIMUM number of PCIe LANES required to function as a GPGPU device:

A. For G80 cards;

B. For single G92 cards with a version 1 PCIe CONNECTOR;

C. For single G92 cards with a version 2 PCIe CONNECTOR;

D. For dual G92 cards with a version 1 PCIe CONNECTOR;

E. For dual G92 cards with a version 2 PCIe CONNECTOR?

Since the G80 cards do not support PCIe 2.0 I assume that the version of the CONNECTOR slot has no influence on the number of LANES required. Thanks for any input or reference to documentation on this question.

Skippy

I don’t think there’s a minimal lane requirement. I guess you can even install GPU on a x16 PCIe 1.0 slot with only x1 speed (that is, 1 lane), but I doubt there’s such mobo.

I think you may be correct. Devices and connectors are technically supposed to auto-negotiate the number of lanes used. I was hoping to hear from someone who has tried a 9800GX2 on an eight lane slot. I am trying to decide between two motherboards, one with four 16 lane slots and the other with two 16 lane and two 8 lane. Device to host memory bandwith is not my highest concern but I can’t afford to make the wrong choice and there is a big cost difference.

Skippy

You can install 9800GX2 on slot with x8 speed for sure. I guess you are choosing from Skulltrail to other 4 slot mobos with 790FX chipset (or nForce Professional 3600+3050 chipset). Because Skulltrail might be the only mobo that is capable of running 4 GPUs all at x16 speed, is that right?

Note that Skulltrail only supports PCIe 1.0, not 2.0. Anyway, since host<–>device bandwidth is not a concern for your application, both should work for you.

Skulltrail or Asus L1N64-SLI WS/B.

Skippy