BIOS Feature Request - Undervolting for Ryzen 7040 Series

The latest update for SteamOS includes options for CPU and GPU undervolting in the BIOS. Given that Insyde supplies the BIOS for both Framework and the Steam Deck, hopefully Framework can eventually get Insyde to include these features.


+1 for that!

AMD officially says that the 7940hs is the only 7040 series CPU that supports undervolting.

Inside could probably enable it anyway if they decided to, however I doubt they would be willing to enable support for something that isn’t officially supported (could get them in trouble with AMD).

Not sure where you got that info. From the product pages of both processors, I see that the Ryzen 9 7940HS has curve optimizer unlocked while the Ryzen 7 7840U does not but nowhere on the page does it mention undervolting support. And curve optimizer is not the same as undervolting.

I don´t think they want any more Stability relatet problems.

If they have to support guys who undervolt it´s probably to mutch.

Undervolting is pretty safe as even if there are issues with the undervolt, you just do a BIOS reset and it resets the values.

If Framework does decide to include undervolting support, the benefit for them is it can extend the battery life of their laptops as well as reduce heat and fan noise. All of these are benefits that are attractive to a lot of people.

Also, this isn’t some niche feature. A few years ago, all laptop chips supported undervolting and some would even come out of the factory already undervolted. However, Intel decided to lock down the feature because of SeCuRiTy.

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Curve Optimizer is essentially per core undervolting.

It’s possible that something is different with Zen4, but a behavior that I have observed on my Zen2 CPU (and IIRC was confirmed as intended behavior by AMD’s head of technical marketing) is that when an offset undervolt is applied the boost algorithm starts requesting up to 0.05v additional voltage so that it ends up with the same voltage after the undervolt. If that doesn’t work then it starts clock stretching (which reduces performance and reduces the voltage the CPU needs to maintain stability).

I think the reason for this is so that if the motherboard has poor voltage regulation or something like that (anything that effectively undervolts the CPU) the boost algorithm will make sure the CPU still gets enough voltage to remain stable.

Curve Optimizer however instructs the boost algorithm to accept the reduced voltage and accept possible instability.

On my Zen2 CPU when I apply a 0.04v undervolt the reported voltage and power consumption stays the same, as does performance.

However when I apply a larger undervolt (ex. 0.06v+) it starts clock stretching. I see similar (sometimes slightly better) performance in Cinebench and average framerate in games, but the 1% lows are severely impacted and stutter increases dramatically.

So undervolting without curve optimizer is definitely problematic on Zen2 and I think it’s also problematic on newer Zen CPUs (definitely seen reports of it on Zen3, not 100% about Zen4).

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Definitely want this on my incoming 7940HS F16. Undervolting is the key to unlocking a huge improvement in battery life.