from Hacker News

How to reenable undervolting in 2020 Dell Laptops by editing EFI variables

by hmm37 on 4/21/24, 10:46 AM with 16 comments

• by hmm37 on 4/21/24, 1:34 PM

  This method works because many system bioses apparently just hide many setup options, and therefore if you can find these options, you can flip the switch by editing EFI variables. Doing so isn't that difficult as the blog entry states.

  So this method could also work for many other different laptops to reenable undervolting or overclocking, etc.

• by inamberclad on 4/23/24, 4:00 AM

  I'm rewriting an embedded BIOS for an Intel processor at work and It's been a bit of a clicking point for me about how modern X86 really works. Nothing EFI or the like, but still very instructive.

  Now if only I could get DCI to work...

• by hu3 on 4/23/24, 11:28 AM

  I followed a similar technique to undervolt an Acer Predator with an i7 11800H processor by -100.06 mV.

  And the result was a 15 celsius reduction in average CPU temperature and improved performance, incredible. I can rarely hear fans now.

  I wonder why isn't this the norm. Perhaps some chips become unstable?

  This is the guide I followed on Youtube: https://www.youtube.com/watch?v=X_OFOmfjs6k

  And here is a relevant screenshot of the bit to be flipped in the video: https://i.imgur.com/xsG0jSE.jpeg

• by banish-m4 on 4/23/24, 8:07 AM

  I use TPFanControl and ThrottleStop on a T480. Without it, there is a pathology where it gets stuck in an upper frequency limit of around 900 MHz when it should peak to around 4 GHz (although the official Turbo Boost speed is 3.4 GHz).

• by rldjbpin on 4/24/24, 9:01 AM

  word of caution - better have a secondary computer and easy access to bios programmer before doing this.

  just downgrading bios (supposedly supported by the laptop manufacturer as an option in the bios) bricked a laptop of mine and it required scouring the internet to find the solution.

  it is a shame that despite all of this you still are dependent on the os and its ecosystem to apply the undervolt. disabling virtualization and wsl is a very poor sacrifice for letting throttlestop work.

  editing EFI variables would be worth it if it could allow you to apply undervolting right then and there!

• by puzzlingcaptcha on 4/23/24, 8:42 AM

  Is it also feasible on AMD platform? I have an embedded board with Ryzen 3200G that does not allow over/underclocking I would be interested in getting it to work there.

• by ogurechny on 4/23/24, 1:16 PM

  > And unlike Intel laptops of the past, many in 2020, including the XPS, Vostro, and Inspiron, have undervolting disabled by default due to the Plundervolt vulnerability.

  Aaand SGX is now deprecated. Therefore, almost useless technology (aimed at big guys who would want to have a safe space protected from computer users and owners) prevents useful one from working. Keeping priorities straight!