R730 needs 2 CPU's to use PCI slots for GPU?

Question

I have an R730 with PCI Risers 2 and 3 installed, with the goal of using it as a GPU server. Our supported card, AMD FirePro S9150, doesn't show up at all in Lifecycle Controller or in OS (using lspci, Centos 6). In BIOS, the 6 slots listed under "slot disablement" are also listed as enabled (assuming these refer to PCI slots anyway, and that if they say "enabled" it doesn't mean "disablement is enabled" and thus they're actually disabled?)

Dell support believes I need a 2nd CPU in the system for the riser 2 & 3 pci slots to be usable. That seems to be based on this part of the R730 Owner's Manual:

GPU card installation guidelines
• Ensure that both the processors are installed.
• The processor must be of 135 W or less.
• The processor must use a GPU kit low-profile heat sink.

But I thought I'd find out if anyone knows for sure, b/c the above working is a little ambiguous. The first requirement says "both processors", but the next two are singular.

Thanks

-Michael

Daniel My · Accepted Answer

If it absolutely won't work (regardless of whether it's validated/supported), then that's find, I've just been trying to find out for certain.

We have tried to make it work to the best of our ability and it is not working. It appears that the 2 CPU requirement is not merely a suggestion. It appears to be a hard requirement that will limit functionality.

Thanks

DELL-Josh Cr · Answer

Hi,

The only configuration that we have validated includes two CPUs. It may be possible to have it work if you have the alternate 3rd riser with the single X16 slot, two 1100w power supplies and the GPU enablement kit.

mstauffer · Answer

Thanks Josh. We do have the 3rd riser with a single slot (at least, the one labeled Riser 3). What would need to be done to make it work? And why would we need two 1100W PSU's? What role does the GPU enablement kit play other than providing low-profile heat sinks and the GPU power cables?

mstauffer · Answer

We have a single 1100w PSU, which you sold to us when we said we were trying to get this system running a GPU. But you're say we have to have two of them? 1100w should be enough, no?

And as for the specifics of the kit, which we received in order to get a power cable, is there anything beyond the power cable and the low-profile heat sink that is required? It came with some DIMM blanks, but those aren't required to be installed, correct?

Thanks

DELL-Josh Cr · Answer

Both the GPU enablement kit and the 1100w power supplies are requirements for GPUs to work and the system to be able to supply the proper power to the card. The GPU that you are using requires more power than is available through the PCIe slot.

DELL-Josh Cr · Answer

Correct, 1100w should be enough, dual 1100w is only needed for K80 GPU. The memory blanks and heatsink are just for airflow and should not prevent it from working.

mstauffer · Answer

OK great. In your first reply you thought there was a way to get it working with a single CPU as long as we have Riser 3 (which we do). Can you elaborate?

Daniel My · Answer

OK great. In your first reply you thought there was a way to get it working with a single CPU as long as we have Riser 3 (which we do). Can you elaborate?

If you have the optional riser 3 you may be able to populate a GPGPU with a single CPU. Riser 3 default is a 2 slot riser. The optional riser is a single x16 length and width slot. If you have that optional riser you may be able to populate a GPGPU. We do not sell or validate single CPU GPGPU configurations, but I don't see a technical reason why it would not work.

Thanks

mstauffer · Answer

Yes, we have a single-slot Riser 3, so dual-width GPGPU fits in there. I have the appropriate power cable connected to riser and GPGPU (AMD FirePro 9150, which is listed as supported on PE R730). But the card doesn't show up at all in lspci (linux) or in Lifecycle Controller (which the PCIe slots as empty). I've tried with a couple NVidia cards too, they don't show up at all (which they should, even if they aren't officially supported).

What's the trick to getting it to work with a single CPU? Thanks.

Daniel My · Answer

What's the trick to getting it to work with a single CPU? Thanks.

There is no trick. You are trying to run a configuration that is not validated and it is not working. All of the documentation states that 2 CPUs are required. I'm not sure of the exact technical reason of the 2 CPU requirement and I see no reason that it needs to be stated.

If you want to try to run configurations that are not validated or ignore stated requirements then we cannot guarantee functionality.

Thanks

mstauffer · Answer

Alright, thanks for looking into it. We'll bite the bullet and get a 2nd cpu.

mstauffer · Answer

I was replying to your earlier statement:

"We do not sell or validate single CPU GPGPU configurations, but I don't see a technical reason why it would not work."

And to a similar one by Josh who thought it may work with a single CPU. If it absolutely won't work (regardless of whether it's validated/supported), then that's find, I've just been trying to find out for certain.

PowerEdge Hardware General

R730 needs 2 CPU's to use PCI slots for GPU?

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