[Guide] Dell XPS 13 9360 on MacOS Sierra 10.12.x - LTS (Long-Term Support) Guide

[jkbuha]

-250mV? I can barely get -125mV (on full load).
Have you run all stress tests (Prime95, 3D etc)

Also - are you using active cooling or heatpads?

 

[egore]

-250mV? I can barely get -125mV (on full load).
Have you run all stress tests (Prime95, 3D etc)

Also - are you using active cooling or heatpads?

Yep, 250mV. I run Geekbench to confirm on MacOS. I did repaste and heatpads.

 

[elvinan]

My xps 9360 have QHD+ screen, so default video memory is 64MB and I cannot find DVMT on BIOS to set 128MB, please help me!

1) BIOS DVMT pre-alloc patching from 32MB to 128MB (setup_var 0x785 0x04)
2) BIOS DVMT max-alloc patching from 256MB to MAX (setup_var 0x786 0x03)

 

[the-darkvoid]

Yep, 250mV. I run Geekbench to confirm on MacOS. I did repaste and heatpads.

Without modifying the BIOS variable, I was able to set any value really. So you might want to make sure your EFI unlock flags are set.

 

[ninjashrimp]

Hi Mark,
Thanks for linking this. I'll give a try with the AppleALC and remove the Voodoo one and look into the sleep specific issues.
Thanks!

I did this as well and everything seems to work well except the headphone jack doesn't seem to produce any sound. When I plug in headphones they are detected but no sound comes out. Are you guys experiencing the same or did I mess up somewhere?

 

[jkbuha]

Yep, 250mV. I run Geekbench to confirm on MacOS. I did repaste and heatpads.

Did some further research after I thought a bit about this. 250 is the maximum range of the under/over-volt registers, as they're only 8-bit on the Dell. So unless there's a super-resistant die lattice out there, it's likely that you've just not enabled the registers for overclocking (which in turn should enable undervolting).

Also - and more pertinently, there should be higher GB scores with each step you undervolt, as you are further away from the TDP ceiling. What are the GB differences, say at 0, -125, -250?

 

[egore]

Did some further research after I thought a bit about this. 250 is the maximum range of the under/over-volt registers, as they're only 8-bit on the Dell. So unless there's a super-resistant die lattice out there, it's likely that you've just not enabled the registers for overclocking (which in turn should enable undervolting).

Also - and more pertinently, there should be higher GB scores with each step you undervolt, as you are further away from the TDP ceiling. What are the GB differences, say at 0, -125, -250?

I'm sure you are correct here. Currently at -600 -600 -75 and running strong. lol -75 for cache is active though, as a setting any lower causes a freeze. CPU and GPU appear not to be active, as -600 is likely unrealistic.

How do I go about enabling undervolting in the BIOS?

 

[jkbuha]

Setting: CFG Lock, Variable: 0x4DE
Option: Disabled, Value: 0x0
Option: Enabled, Value: 0x1 (default)

Setting: OverClocking Feature, Variable: 0x64D
Option: Disabled, Value: 0x0 (default)
Option: Enabled, Value: 0x1

Setting: XTU Interface, Variable: 0x64E
Option: Disabled, Value: 0x0 (default)
Option: Enabled, Value: 0x1

0x4DE -> 00
0x64D -> 01
0x64E -> 01

That should get you going. Then experiment with undervolting and report back.

 

[egore]

Setting: CFG Lock, Variable: 0x4DE
Option: Disabled, Value: 0x0
Option: Enabled, Value: 0x1 (default)

Setting: OverClocking Feature, Variable: 0x64D
Option: Disabled, Value: 0x0 (default)
Option: Enabled, Value: 0x1

Setting: XTU Interface, Variable: 0x64E
Option: Disabled, Value: 0x0 (default)
Option: Enabled, Value: 0x1

0x4DE -> 00
0x64D -> 01
0x64E -> 01

That should get you going. Then experiment with undervolting and report back.

0x4DE -> 00 (was already set)
0x64D -> 01 (changed)
0x64E -> 01 (changed)

VoltageShift values:
-(any number) -(any number) -75 (max before freeze)
No improvement/change in GeekBench scores.

In other words, it appears the BIOS modifications did not unlock undervolt capabilities. No change in results from prior to changing the BIOS.

 

[the-darkvoid]

0x4DE -> 00 (was already set)
0x64D -> 01 (changed)
0x64E -> 01 (changed)

VoltageShift values:
-(any number) -(any number) -75 (max before freeze)
No improvement/change in GeekBench scores.

In other words, it appears the BIOS modifications did not unlock undervolt capabilities. No change in results from prior to changing the BIOS.

User @arehep mentions in this post that it should work without BIOS unlock. I only got undervolting working reliably through EFI var settings though.