Building on my work on 2021-08-01.

ThrottleStop didn’t work on my Dell XPS 9343.
Intel XTU said the Power Limits were locked.

Found some tutorials for Dell XPS to unlock this.

Summary

  • Dump UEFI with FPTW64.exe for your Intel ME version.
  • Use UEFITool to search for “CFG Lock”, as text, and extract the PE32 file
  • Use Universal IFR Extractor on the PE32 file.
  • Read the text file and search for “ lock” stuff.
  • When setting with setup_var $varstore $offset $data, pay attention to Offset $offset is: $old_data to doublecheck the old status.

Things I wish I learned before

  • Check every change with a HWInfo64 report. If a change is not visible in HWInfo64, no dice.
  • Making a CSV-report with HWInfo64 before and after and diffing is a nice way to check for effects.
  • This would’ve saved me quite rabbitholes.

Things I learned

  • modGRUBShell.efi didn’t work for me. This one worked for me.
  • Putting on a USB Stick as \efi\boot\bootx64.efi works, but putting on main efi partition as grub_setup_var.efi and adding to boot menu is more comfortable!
  • setup_var couldn’t find CpuSetup. Found the name Setup in the IFR as VarStore: VarStoreId: 0x2 Name: Setup
  • ThrottleStop and Intel XTU couldn’t change PL1 or PL2, because they were locked. ThrottleStop shows a lock. HWInfo64 shows: 
    "CPU Power Limit 1 - Long Duration:"," (15.00 W) (28.00 sec) [Locked]"
"CPU Power Limit 2 - Short Duration:"," (25.00 W) (2.44 ms) [Locked]"
  • Setting Package power limit lock: 0x9 to 0x0 changed 
    "CPU Power Limit 1 - Long Duration:"," (15.00 W) (28.00 sec) [Unlocked]"
"CPU Power Limit 2 - Short Duration:"," (25.00 W) (2.44 ms) [Unlocked]"
  • PLx changes in ThrottleStop didn’t become visible in HWInfo64 or active until I ticked the “Disable and Lock Turbo Power Limits” box in the FIVR menu.
  • Mission accomplished! No more Power Limit Throttling during Cinebench or 3DMark.
  • But now I was running into thermal limits with the CPU package at 100c.
  • Adding thermal pads to the CPU heatsink and heatpipe to sink heat into the alumium bottom cover is pretty effective.
  • I got these thermal pads.
  • I can keep Snowrunner running at ~20w, at around 80c, without throttling. Yay! Now it’s a steady 14fps instead of dipping to 13 every now and then!

What didn’t work

  • Setting any of the following to 0x0 has no HWInfo64-visible effect. 
    Overclocking lock: 0x4
VR Current value lock: 0xE
Config TDP LOCK 0x23
CFG lock: 0x37
Platform power limit lock: 0x46
  • Neither does setting Cpu Power Limit1: 0x18 to 25.
  • Or changing Configurable TDP 0x22 from NOMINAL to UP.
  • Intel XTU didn’t work great for me. Changing the PL1 to 25w in XTU was visible in HWInfo64.
  • However, after 30-60 seconds of Cinebench it still limits to 15w with a Power Limit when using Intel XTU.