TrueNAS Scale CPU Undervolting

Hello, I’m new here and I have a rather unusual question. Is it possible to undervolt an Intel processor, specifically the i7 7700T? I know that on Windows this is possible with software like ThrottleStop, and I’ve heard that on standard Linux systems, there are many applications that can do this as well. But what about TrueNAS Scale? Can I simply install the appropriate software directly in the TrueNAS Scale Terminal and start undervolting, or would it be better to create a virtual machine specifically for this purpose? I should mention that I’m relatively new to the world of Linux, having used Windows my entire life, so I might make some mistakes in my thinking. Thank you in advance for your help.

P.S. I should add that I’m aware this hardware is outdated and it would be best to upgrade to something better. The time for an upgrade will come soon, but part of the fun is pushing this old machine to its limits.

Undervolting is overclocking, but instead of increasing the voltage and clock speed you just drop the voltage.

I last bothered to overclock on X99. And back then you did it in the bios.

Personally I wouldn’t bother.

Like overclocking, undervolting can cause subtle errors and this can cause data corruption. Which is not worth it.

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I’ve always preferred to do my overclocking / undervolting in BIOS.

Usually with Truenas we recommend rigorous stability testing and staying away from all overclocking. This will introduce a lot more effort in stability testing for you.

OTOH at least in my overclocking days, that was restricted to the K models of Intel. Is the T model even susceptible to overclocking? What’s your mainboard?

I personally wouldn’t bother for truenas to be honest, the savings will probably not outweigh the stability risks. If you even can do it on your hardware.

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IIRC you could under clock a non-k with an over clock friendly board.

Undervolting is similar I believe.

Oh okay, I don’t know that for sure. Hopefully we both steered OP away from it anyway.

Undervolting is a lot harder to get stable in my opinion, with overclocking you can at least push the system and see if it crashes. With undervolting it may take days for the system to crash during idle (at least in my experience) or as you said introduce subtle errors that may not directly crash the system (but that should also go for OCing though).

I understand what undervolting is and that it can cause errors if done improperly, but that’s not the point of my question. If I could do this through the BIOS, I wouldn’t be asking this question. However, the device I want to do this on doesn’t have this option in the BIOS because it’s an OEM device. The only possibility is to do this through some software, and the information I really need is whether I can install something like this directly on TrueNAS, via ‘apt install’ from the terminal, or would it be better if I created a virtual machine, assuming it allows such a degree of influence on the operation of the entire system.

Imo no. Truenas is a appliance like OS. There are lots if apps available but as far as i know, nothing like this.

May I ask the reason for this? The 7700T has a TDP of 35W, which is low. I have a completly passive cooled office pc wirhout any moving parts with an old i7 3770T that has 45W TDP.

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We cannot assume any left out information :person_shrugging: you should have specified that then.

As far as I know this functionality is disabled / restricted deliberately.

TDP is irrelevant: A NAS will spend most of its time in idle… and a ‘T’ CPU idles at the same level as a non-‘T’.

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This is in-and-of-itself is probably your show stopper. Some hacked together overclocking programs on Windows can sometimes do this, 1usmus as an example makes these cool pieces of kit for Ryzen, as an example:
Yuri Bubliy | creating software for Ryzen community | Patreon

But because you are running an OEM device, “Official” programs like Intel XTU will not work, even if they were supported on Linux/TrueNAS.

TrueNAS is an appliance, apt is not available unless you enabled the unsupported Developer Mode, and even if it weren’t I am not aware of a program that will do what you are asking…at least not one I’ve actually tested and used.

or would it be better if I created a virtual machine, assuming it allows such a degree of influence on the operation of the entire system.

Virtual Machines do not work that way, so this would not be possible.

Neither of those statements are strictly true, I’ve had NAS’s in production eating up CPU left and right. It depends on alot of factors.
As for power: A “T” series CPU will consume, at 10-50% utilization, a measurable degree less power than a non T series CPU. It’s just that 50-100% that delta grows wider.

But I disagree with OP on two fronts: 7700T is a perfectly valid CPU option that still performs well at this task, and I also don’t think trying to get additional efficiency will yield much in the way of cost savings.

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The sanctioned way to “apt install” is inside a Sandbox

I’d be curious if that would work.

Alternatively, you can enable dev mode.

So, what you want to do is find out how you would do this on Debian Linux. Then you can try in Sandbox, or with dev mode enabled.

Here’s a start:
Reddit: Overclocking Tools for Linux (CPU and GPU)

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Instead of undervolting you can investigate setting a wattage limit - there is a solid chance you may have at least basic ‘performance’ vs ‘powersaving’ nonsense OEM level settings in BIOS that would cap wattage of the CPU at the cost of frequency.

I’d strongly avoid undervolting unless you’re experienced as it can manifest interesting instabilities; not something you want on a 24/7 device that is meant to host your precious data. For gaming I love undervolting as I don’t care that my machine might not be stable for more than 3 consecutive days without a WHE being logged (or worse) as it keep me from boiling to death.