Should I Undervolt the Ryzen 9 7940HS?

It doesn’t matter which edition, changing the CPU is impossible. Framework, still being a small company, probably orders those as needed and would run into a problem if too many people first order one CPU just to switch to another as that would fill out their storage capacities unnecessarily with the first ordered CPUs and those are the most expensive part of the whole laptop, I guess.

There are some things to keep in mind when undervolting using Curve Optimizer:

  • Stability: The problem is usually stability during idle and switches between lower and higher powerstates. Hence the lots and lots of people throwing a big CO undervolt at their CPUs and claiming stable after running some load tests. The instability at lower power/voltages can be very subtle and hard to trigger.
  • Clock stretching: This is a protection mechanism at higher points on the voltage/frequency curve to prevent crashes caused by voltages to low for the wanted frequency. Your system will show high clocks but benching can show lower results caused by this behaviour.

Essentially, test stability on the whole frequency range and with spiky/transient loads and check if you actually gain performance by doing more CO offset while controlling other variables (temps,fan speed).
Be prepared to sink a lot of time into this if you want do it properly. I have done it for a desktop 5950X and while it gained me some performance it’s more the fun while tinkering aspect for me than the actual result. Single digit gains on some of the cores. Maybe there is more potential in a laptop because of thermal limits but YMMV.

Did the undervolting reduce power consumption in general, or does the same amount of power wind up used when under load? And would undervolting reduce thermal throttling, or again when it’s under load does it not make a difference?

My experience with the desktop version of the 7000’s is that it reduces both thermal throttling and power consumption as wattage is turned into waste heat. Validated with HWInfo and my UPS, my avg watts pulled on my 7800X3D is around 28-30watts with a ton of tabs and things up and running. 70-80w maximum peaking while gaming.

As mentioned above, For those looking into it, both of the CPU’s per AMD don’t support overclocking officially, while only one (7940) supports offsets. Whether or not they classify undervolting as overclocking, I’m not entirely sure. See 7940 vs 7840 here. Other thing to note with the mobile CPUs is STAPM, when they hit their max thermal sink, they throttle. I think that both GN and Level1 Techs had videos about STAPM due to issues with the recent desktop 8000 apu’s.

Both is achievable. I have gone for performance (mainly single core was important to me) since my desktop is a power hog anyway, but CO gives you higher clocks in the same power envelope in the first step. In low load scenarios that means less power used. If you then limit frequencies/wattage with PBO to reach the same performance as before using CO you should end up with less power even at high load.
I don’t know if it applies to to the monolithic 7000 mobile, but my 5950X can save about 10 watts in idle with slightly lower SOC voltage. Also not for me since my memory is overclocked but noteworthy.