Hi, I have tried undervolting my t480 before, but ran into several issues, I wonder if that was because I was just not doing it correctly? never found a proper guide or tips for it really, anyone have any idea how to properly do it? reading other people鈥檚 stuff, seems it is indeed worth it to try at least.
not much to it, undervolt CPU/GPU/cache in small increments (like, -75 mV at a time) until it starts to freeze or reboot, back off a bit, test for a day or two then set and forget. usually -150 mV is achievable and that makes a significant difference for the battery, coupled with turning turbo off for intel_pstate driver. if it doesn鈥檛 work, bad luck with the silicon lottery and also them models are what 8 years old at this point, so there鈥檚 also wear and tear in the form of electron migration.
This guy鈥檚 right on the money. That鈥檚 about as far as I got with my T470. Be sure to stress test it with some hot, CPU-heavy action to make sure it doesn鈥檛 freeze. I was able to get mine down to about -120 mV, but raising that a little bit made it more stable.
I haven鈥檛 played with undervolting on Linux yet, but I do recall that there was the Plundervolt vulnerability a while back, to which OEMs responded with BIOS updates that disabled undervolting.