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Dell XPS 15 9560 (1.2.5) NVRAM edits
# Set Intel(R) Speed Shift Technology to Enabled
setup_var 0x4BC 0x1
# Set CFG Lock to Disabled
setup_var 0x4ED 0x0
# Set Above 4GB MMIO BIOS assignment to Enabled
# setup_var 0x79A 0x1
# Set EHCI Hand-off to Disabled
# setup_var 0x2 0x0
# Set XHCI Hand-off to Disabled
# setup_var 0x1B 0x0
# Set Low Power S0 Idle Capability to Enabled
setup_var 0x13 0x1
# Set DVMT Total Gfx Mem to MAX
# setup_var 0x796 0x3
# Set Overclocking Lock to Disabled
# setup_var 0x59C 0x0
# Set OverClocking Feature to Enabled
setup_var 0x65C 0x1
# Set XTU Interface to Enabled
setup_var 0x65D 0x1
# Set Core Voltage Offset Prefix to Negative
setup_var 0x664 0x1
# Set Core Voltage Offset to -120 mV
setup_var 0x662 0x78
# Set Uncore Voltage Offset Prefix to Negative
setup_var 0x865 0x1
# Set Uncore Voltage Offset to -100 mV
setup_var 0x863 0x64
# Set GT Voltage Offset Prefix to Negative
setup_var 0x86D 0x1
# Set GT Voltage Offset to -100 mV
setup_var 0x86B 0x64
# Set GT Unsliced Voltage Offset Prefix to Negative
setup_var 0x876 0x1
# Set GT Unsliced Voltage Offset to -100 mV
setup_var 0x874 0x64
# Set PCI Express Root Port 13 to Disabled
setup_var 0x95A 0x0
# DCI killed in recent BIOS version?
# chipsec -m chipsec.modules.common.debugenabled reports DCI Debug is disabled even after setting these
# Set Debug Interface to Enabled
# setup_var 0x59D 0x1
# Set Debug Interface Lock to Disabled
# setup_var 0x59E 0x0
# Set Direct Connect Interface to Enabled
# setup_var 0x59F 0x1
# Set DCI enable (HDCIEN) to Enabled
# setup_var 0x899 0x1
# Set TraceHub Enable Mode to Host Debugger
# setup_var 0xEAF 0x2
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LeLunZ commented Jan 7, 2022

Hey, could you help me a little bit? :)
what's the point in disabling the PCI Express Root Port 13?
And do you know why Overclocking Lock doesn't stay disabled? After each reboot it resets...

BIOS version 1.24.0

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RP13 doesn't appear to be used, but disabling it is likely useless. No idea about Overclocking Lock, sorry.

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gasmonso commented Feb 7, 2022

I'd love to use this information to patch my bios do I can undervolt my 9560. But how do I use this to achieve that? Is there some sort of guide, or at least a clue? Thanks!!

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LeLunZ commented Feb 7, 2022

@gasmonso the variables got extracted from the BIOS.

You can apply these settings above with setup_var

put it on a usb drive and set modGrubShell.efi as boot option.

But be aware you can brick your system.

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gasmonso commented Feb 7, 2022

@LeLunZ Thank you so much! I can't wait to try it out.

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gasmonso commented Mar 7, 2022

Has anyone had any success with the latest BIOS version 1.24.0?? I've only gotten the Speed Shift working. I'd like to get the XTU interface working so I can use that to undervolt, but nothing seems to work.

If you have gotten things working please share what you did. I tried downgrading the BIOS and that didn't work.

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LeLunZ commented Mar 7, 2022

@gasmonso yes. I had success. Try „reset to factory settings“ in the bios menu once. And then try again.

But set the undervolt through these offsets! That’s simpler than xtu.

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Thanks for this! A question on the GT Unsliced:

System is an XPS 15 9560, Bios 1.24.0, using setup_var_vs with the same IDs as above.

  • when reviewing the undervolts in hwinfo or throttlestop I see:
    CPU Core -0.125v
    Intel GPU -0.0996v
    CPU Cache -0.125v
    IGPU Unslice +0.00v
    System Agent -0.125v

Any idea why the IGPU Unslice is not showing as being set equal to the Intel GPU (-0.100v)?

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VGerris commented Nov 29, 2022

Still works for 1.30 BIOS for Precision 5520 , thank you. Needed factory defaults before it worked

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