BIOS Settings to reduce power consumption of AMD EPYC

Hi,

I am using an AMD EPYC 7443P for my Proxmox server.
The chip consumes around 110W or so, when most of the VMs are idle.
I am aware that an EPYC chip will never be as power efficient as e.g. a laptop chip, but I wonder, what specific BIOS settings can I change to reduce power consumption?

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This is a question of what you are willing to pay for. One can either get a RV or a sedan. Both good vehicles in their own right but both radically different in design and purpose. Server CPUs aren’t designed for low power consumption but rather power efficiency, or how much performance per watt they get (aka miles per gallon) whereas consumer CPUs have a complete different focus with total power consumption being the principal concern. And that is a matter of design and purpose. It is assumed that server CPUs are making the owner(s) money and consuming electricity while doing it thus in order to provide that customer with value the CPU needs to make the most of every watt of power consumed. Whereas the consumer CPU market flips that on it’s head. So the question is do you really want to pay to play or are cheaper, more cost-effective solutions available. Perhaps an Eypc 4004 CPU is more suited to your purposes.

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a lot of EPYC boards support cTDP. you can lower it and it will lower the chips overall power usage, at the cost of peak MHZ. if the board does not have cTDP you might be able to lower the max speed and get a similar effect. the 7443p is a good chip but absolutely burns power to make performance. probably excessive in a home lab.

some EPYC boards have no ability to adjust any speed or TDP seeting, but their may be a modded BIOS on the web.

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There’s really nothing to optimize and 110 W idle is pretty good, you just can’t make that huge IO die run with less. Just make sure your hypervisor (Proxmox?) has the AMD P-state enabled in kernel and relevant settings for that on the BIOS side are enabled.

The only ways to go lower are 1) remove DIMMs 2) don’t connect PCIe devices and at that point you could just run regular desktop class HW.

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… or go with something like an Epyc Siena 8024P, reported to draw <30 W at idle here, if you need lots of PCIe and/or 6 RAM channels but not a lot of CPU performance.

Edit: Of course, that might have been with no PCIe/NVMe devices connected (it’s a bit unclear from the post). Maybe the IO die draws more with more things hooked up, even at idle, as implied by vvk’s post.

Have a look at AMD’s Workload Tuning Guide.

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Like I said, only 6x RAM and 2x Noctua fans connected in that example.

With 6x RAM, 11 fans (low rpm), 4x U.2 NVMe, 2x HDD, 1x M.2 and 1x PCIe NIC it doesn’t even come close to 110W measured from the wall. Siena is a low power platform.

edit: To be clear, because of the way SIENAD8UD3 motherboard takes power only from CPU 8pin cable, <30W includes CPU, MB (with BMC), RAM and fans.

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Holy crap I may need to consider 8xxx stuff then… That is some incredible efficiency. If only ddr5 rdimms weren’t so insanely expensive…

Same boat as OP. Idling insanely high with low activity. Proxmox with romed8-2t and a 7532. Should check the pstates as well hmm…

You have obviously never run a Ryzen at stock :rofl:

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That 7-seres EPYC IO die never got die shrink, so even on Milan it’s fabricobbled with the 14 nm process, whereas Genoa/Siena has it on the much more modern 6 nm process.

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Ship that hunk of junk to me and I’ll begrudgingly send you a T series Intel sku to replace that power hawg…

But as others have stated, enterprise gear runs hot and you’ll pay for the potential performance.

That is how all 4 of my Ryzens run.