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BWeis3
Beginner
1,091 Views

Intel NUC: Which have bios support for pcie spread spectrum control?

For certain devices connected to the PCIe it's required to switch off PCIe spread spectrum.

Which of the Intel NUC kits (i7 based preferred) do have support for this feature in the BIOS / UEFI?

Thanks for your hints or pointers.

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6 Replies
jema
Novice
125 Views

I'm not sure any of them have any connectors that are available to you as a user that use PCIe except the m.2 port.

I think you'll have more success asking if a certain piece of hardware works with the nuc you're considering, or checking the compability docs.

Edit: Isn't spread spectrum off by default? I can't recall having ever seen it being enabled in my many years of tinkering with computers.

n_scott_pearson
Super User Retired Employee
125 Views

That is correct. Since the M.2 connector is only intended to house a M.2 SATA/NVMe SSD drive or an Optane Memory module, no support for general-purpose PCIe devices is provided.

Perhaps you should explain why you feel you need this capability.

...S

BWeis3
Beginner
125 Views

Scott, Jema,

Thanks for your time to reply to my question.

We are working on a very dense FPGA server for the cloud https://www.zurich.ibm.com/cci/cloudFPGA/ IBM Research - Zurich, cloudFPGA.

Networking on board uses an Intel FM6000 series Ethernet switch which connects to PCI, spread spectrum off only.

I'm looking for a nice little board which fits into the chassis beside the FPGAs - a NUC looks interesting for our needs. As long UEFI supports to switch PCI spread spectrum off explicitely. Spread spectrum isn't off by default - we have some time consuming experience already.

Therefore again my question: do any of the Intel NUC kits support switching off PCIe spread spectrum?

Best regards,

Beat

jema
Novice
125 Views

Your project sounds really cool but as far as I can tell a nuc isn't for you, I think you will have more luck with itx, m or thin. Considering where you work there ought to be an account manager or two who could help you.

I checked one of my nucs and there is no setting for spread spectrum.

n_scott_pearson
Super User Retired Employee
125 Views

I have to agree with Jema. As I said, the only source of PCIe lanes in the NUC is the four lanes routed to the M.2 connector and this connector is intended to support a M.2 SATA/NVMe SSD or an Optane Memory card. You could request that support be added for general-purpose use of these PCIe lanes. This would be an uphill battle (it could raise validation costs significantly), but you never know. To make such a request, you would need to contact Intel Customer Support directly and have them facilitate contact with the PMEs responsible for this decision-making.

...S

rhoul1
Beginner
125 Views

Hello Beat,

Did you manage to enumerate the FPGA with a NUC at all?

I have a project in which a NUC would be great too to communicate with an FPGA.

Did find out how to disable the spread spectrum on a NUC board? Or did you find a good alternative?

Thanks,

raph