Yet Another Hardware Question PCIe Requirements

Accelerated Computing CUDA CUDA Programming and Performance
1

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

2

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.

3

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.

4

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

5

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.

6

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

7

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.

8

Skulltrail or Asus L1N64-SLI WS/B.

Skippy