X58 + Xeon X5675 needs SpeedStep off going from 12.2 to 12.3+

[nekapsule]

Hi there,

I struggled for a while figuring why my perfectly working Monterey 12.2 wouldn't boot anymore after updating to 12.3 (or anything after that).
For some reason, I now have to disable SpeedStep in the bios, otherwise I get into a boot loop when the CPU detection occurs.

Took me a while to figure why because it was not panicking, just hanging or hanging for a few secs then reboot.
Lowering the number of active cores in the Bios started triggering a Kernel Panic and that's where I saw the culprits were ApplePowerManagement and X86PlatformPlugin.

Once I knew the CPU was the issue, I tried various things, including disabling SpeedStep, and that did the trick.
Now I lost Turbo, and even loading a modified MacPro4,1 power profile like I did before doesn't restore it.
I'll keep investigating but no turbo is still better than no boot at all...

 

[nekapsule]

Prior to describing the below method, I had managed to re-enable speedstep in the BIOS by generating an SSDT with ssdtPRGen. But since X86PlatformPlugin was still used, it never really used the P States (only C-States worked) and never used the turbo multipliers.

Here's the catch:

It turns out Monterey 12.3 removed full power management support for older CPUs, resulting in loading X86PlatformPlugin to handle PM instead of ACPI_SMC_PlatformPlugin:

Fix Power Management Support in macOS 12.3 Beta 1 · dortania/OpenCore-Legacy-Patcher@f7f890d

Closes https://github.com/dortania/OpenCore-Legacy-Patcher/issues/930

github.com

I grabbed that ASPP-Override.kext and tried with the SSDT I had generated from ssdtPRGen but that still didn't enable turbo modes. On the other hand, it was now loading ACPI_SMC_PlatformPlugin.

I then added my trusty MacPro41-PowerProfile.kext (from https://github.com/vin047/MacPro41-PowerProfile), thinking it would use it in combination of ASPP-Override.kext but it didn't.

I combined the 2 by copying the IOPlatformThermalProfile key from MacPro41-PowerProfile to ACPI_SMC_PlatformPlugin but I still didn't have P States.

The final step was to actual REMOVE the SSDT as my other config running Big Sur with the same CPU doesn't need it.

And... Tada! Turbo multipliers are now enabled:

System Average frequency as fraction of nominal: 95.11% (2920.03 Mhz)
CPU Average frequency as fraction of nominal: 99.70% (3060.73 Mhz)
CPU Average frequency as fraction of nominal: 105.21% (3229.95 Mhz)
CPU Average frequency as fraction of nominal: 98.21% (3014.92 Mhz)
CPU Average frequency as fraction of nominal: 104.77% (3216.44 Mhz)
CPU Average frequency as fraction of nominal: 81.87% (2513.39 Mhz)
CPU Average frequency as fraction of nominal: 104.50% (3208.27 Mhz)
CPU Average frequency as fraction of nominal: 99.30% (3048.60 Mhz)
CPU Average frequency as fraction of nominal: 105.28% (3232.08 Mhz)
CPU Average frequency as fraction of nominal: 93.02% (2855.66 Mhz)
CPU Average frequency as fraction of nominal: 106.52% (3270.03 Mhz)
CPU Average frequency as fraction of nominal: 104.76% (3215.99 Mhz)
CPU Average frequency as fraction of nominal: 106.18% (3259.61 Mhz)

I attached the modified the kext for those running the same type of setup.
Remember to NOT load any SSDT generated from ssdtPRGen, just let the stock ACPI be recognised.

Hope this helps!

 

[nekapsule]

Following up on this, I noticed Single core scores in Geekbench were always better without MacPro41-PowerProfile.kext or my newly modified ASPP-Override.kext. It turns out C-State C6 is the culprit and introduces lag to go back from C6 to C3 when a single core suddenly needs to go "faster".

I got rid of that performance loss by limiting C-States to C3 instead of C6 in the BIOS.
It makes the CPU less power efficient and probably a bit hotter, but single core scores are now excellent.

After overclocking the X5675 to 3.9Ghz, this is what I get:

https://browser.geekbench.com/v5/cpu/21096373

It's actually better than what I get on the X5690 overclocked to 4.03Gz, because BCLK is "only" 150Mhz on the X5690 vs 170Mhz on the X5675.

 

[dk1306]

hey, thanks for posting. I actually have a P6T Deluxe V2 with i7-960 and am still struggling to get Power Management. I also use Aspp-override kext together with all of the other Power kexts and patches from OCLP generated for MacPro5,1. May I ask, if you can share your EFI and maybe your BIOS Settings, too?

 

[nekapsule]

I’ll do that later but first, you shouldn’t use any other kext from OCLP, just the modified aspp-override I posted. Enable speedstep and c-steps in the bios. You can tweak c-states and only use up to c-3 as I explained if you want to be a bit more aggressive with power.

Make sure you don’t load any ssdt related to cpu.

What Smbios do you run? I have patched aspp-override for MacPro 6,1 as I’m running this smbios from get Handoff working.

 

[dk1306]

I’ll do that later but first, you shouldn’t use any other kext from OCLP, just the modified aspp-override I posted. Enable speedstep and c-steps in the bios. You can tweak c-states and only use up to c-3 as I explained if you want to be a bit more aggressive with power.

Make sure you don’t load any ssdt related to cpu.

What Smbios do you run? I have patched aspp-override for MacPro 6,1 as I’m running this smbios from get Handoff working.

Thank, I'm on MacPro7,1. I removed all of the OCLP stuff anreplaced ASPP kext with yours, als changed to C3. On HWMonitorSMC2 I'm getting radings either 1,5ghz or 3,2ghz(base clock), but never 3,4(boost)
Here are my powermetrics:

CPU Average frequency as fraction of nominal: 89.52% (2864.66 Mhz)
CPU Average frequency as fraction of nominal: 93.42% (2989.40 Mhz)
CPU Average frequency as fraction of nominal: 94.66% (3029.08 Mhz)
CPU Average frequency as fraction of nominal: 88.59% (2834.81 Mhz)
CPU Average frequency as fraction of nominal: 92.88% (2972.16 Mhz)
CPU Average frequency as fraction of nominal: 93.21% (2982.59 Mhz)
CPU Average frequency as fraction of nominal: 88.01% (2816.44 Mhz)
CPU Average frequency as fraction of nominal: 86.11% (2755.60 Mhz)
CPU Average frequency as fraction of nominal: 87.77% (2808.65 Mhz)
CPU Average frequency as fraction of nominal: 97.92% (3133.34 Mhz)
CPU Average frequency as fraction of nominal: 90.32% (2890.25 Mhz)
CPU Average frequency as fraction of nominal: 95.22% (3046.95 Mhz)
CPU Average frequency as fraction of nominal: 90.56% (2897.96 Mhz)
CPU Average frequency as fraction of nominal: 93.57% (2994.31 Mhz)
CPU Average frequency as fraction of nominal: 90.45% (2894.47 Mhz)
CPU Average frequency as fraction of nominal: 96.47% (3087.12 Mhz)
CPU Average frequency as fraction of nominal: 94.86% (3035.51 Mhz)
CPU Average frequency as fraction of nominal: 98.41% (3149.12 Mhz)
CPU Average frequency as fraction of nominal: 97.94% (3134.11 Mhz)
CPU Average frequency as fraction of nominal: 98.85% (3163.06 Mhz)
CPU Average frequency as fraction of nominal: 97.86% (3131.65 Mhz)
CPU Average frequency as fraction of nominal: 99.23% (3175.26 Mhz)
CPU Average frequency as fraction of nominal: 97.98% (3135.24 Mhz)
CPU Average frequency as fraction of nominal: 99.48% (3183.47 Mhz)
CPU Average frequency as fraction of nominal: 96.91% (3101.06 Mhz)
CPU Average frequency as fraction of nominal: 100.16% (3205.07 Mhz)
CPU Average frequency as fraction of nominal: 98.32% (3146.13 Mhz)
CPU Average frequency as fraction of nominal: 100.17% (3205.52 Mhz)
CPU Average frequency as fraction of nominal: 99.08% (3170.70 Mhz)
CPU Average frequency as fraction of nominal: 100.12% (3203.72 Mhz)
CPU Average frequency as fraction of nominal: 98.72% (3159.00 Mhz)
CPU Average frequency as fraction of nominal: 100.11% (3203.53 Mhz)

Do you think it's working?
I've attached also geekbanch before vs after

 

[nekapsule]

Did you enable speedstep in the bios?
Without Speedstep it will never turbo and go over 100% powermetrics.

I’ll have a look at what could prevent the kext from enabling turbo with your Smbios but you could try 6,1. There’s no real reason to use 7,1 with that config. Anything you’re missing with 6,1?

 

[dk1306]

Did you enable speedstep in the bios?
Without Speedstep it will never turbo and go over 100% powermetrics.

I’ll have a look at what could prevent the kext from enabling turbo with your Smbios but you could try 6,1. There’s no real reason to use 7,1 with that config. Anything you’re missing with 6,1?

Well... Ventura support

edit: Yes, I did enable Speedstep

more edit: with 6,1 I couldn't enable DRM on monetery back in the day, that's why I switched. Also had to enable unfairgva

 

[nekapsule]

Well... Ventura support

edit: Yes, I did enable Speedstep

more edit: with 6,1 I couldn't enable DRM on monetery back in the day, that's why I switched. Also had to enable unfairgva

Ventura support on a CPU without AVX is a dream till we get AVX emulation.

I still changed 6,1 to 7,1 in the kext, that would have not enabled the correct frequency tables with your smbios, try this new one:

 

[nekapsule]

Once you enable this kext, search for "platformplugin" in IoRegistryExplorer and make sure you have a PerformanceStateArray property: