Cannot get 4.2ghz+ SSDT working, tried everything!

[someoneelse]

Here's my setup:

i7 2600k
Gigabyte Z68XP-UD3P, UEFI
8GB RAM
Radeon 6870
Mac OS 10.8.5
DSDT-less installation, Multibeast 5.5, MacMini 5,1 SMBIOS

Some time ago (Before flashing to UEFI), I had this thing up in the mid-4ghz range no problem. Once I flashed with UEFI and installed 10.8, I didn't really bother until recently. I installed the default 4.2ghz SSDT and have been able to crank it up no problem. However, getting it past that point has been utterly impossible. What I've done thus far:

-Ensured that I'm only pushing the turbo up, not the multiplier
-Make sure it's something akin to 43, 42, 42, 42 in the turbo settings.
-Checked voltages to make sure they'd work (they darned well should)

After verifying that, I tried:

-A 4.7ghz SSDT provided here.
-An autogenerated SSDT from MaciASL that went up to 4.8ghz
-Trimming that autogenerated SSDT down to 8 P-States, topping out at 4.3ghz

Nothing works. Any attempt to push the turbo anywhere north of 4.2ghz spits up a "P-State Stepper Error 18 at step 29 in context 2 on CPU X" kernel panic. I recall CPU 2 and CPU 4 being mentioned, but that's probably arbitrary. Stepping works when below 4.2ghz no problem.

I did notice one oddity: No matter what P-States I put in the SSDT.aml in /Extra, they do NOT get recognized. At all. Using AppleCPUPowerManagementInfo.kext, I see what appears to be the stock steppings being reached. No set stepping in the SSDT is used, or at least it's inserting its own when convenient. Right now I have the following steppings in the SSDT.aml (and yes, I cut down the APSS value to match:

43, 42, 41, 35, 30, 24, 20, 16

What I'm seeing from the ACPMI dump (running at 4.2/4.1/4.1/4.1) is:

16 27 33 34 40 41 42

Either it's only using a few from the top or it's following some sort of formula to calculate ideal P-States, but it's definitely not restricting itself to the SSDT.

Any ideas? Something I missed? I've heard that there's a sort of "maximum" on P-States that can be utilized by the system, but I haven't seen that clarified. I also know that things get a little wonky if you go above 4.2ghz, but again, nothing solid on what exactly that may be. I've dug around on the forum and elsewhere, but much of the information is or could easily be outdated. What else can I try to get this above 4.2ghz?

 

[someoneelse]

Okay, I'm an ijit. I forgot that the Fusion drive setup mandates EFI partition installation, so of course changes to the /Extra folder in the main drive weren't being seen. I pushed an SSDT to both EFI partitions in the terminal along with a Mac Mini 5,3 definition...and could not boot without a KP. Oh well, this gave me a reason to set up a small OS X Backup partition on my backup drive, something I should have done when I installed 10.8. With that done, I was able to remove the SSDT from the EFI partitions and all was well. As a bonus, I can use that to test SSDTs and overclocks with minimal risk as I can just drop a new SSDT in, boot from the backup drive, and see if it works before pushing it to the EFI partition on my Fusion drive. I'm back at 4.2/4.1/4.1/4.1. Now to see if I can go further...

 

[someoneelse]

Bumping because I'm back to square one. Even with a properly-installed SSDT, I still cannot break 4.2ghz without a KP on boot. I don't know what the heck else to do here...

 

[djego]

Hello, I'm in the same situation as you.
I have the same components as you, minus the motherboard that is Z68XP-ud3.
You have managed to make it work again right??

 

[someoneelse]

Nope, still stuck.

 

[djego]

Only thing is that I do not use fusion drive.
In a comment above yours, you say that if you get it working, it would be possible to say how you did it??
That SSDT I have to put in to the 2600k? Those who come with MB 6 does not work for me.
The funny thing is that I have another partition that worked without problems until you update the bios

 

[someoneelse]

It's only working up to 4.2ghz. Beyond that, it doesn't matter what SSDT I use, I get a KP on boot. That was working by simply installing MultiBeast with the 4.2ghz SSDT a while ago and using the one-off trick on the fixed turbo (ie, leave the multiplier alone, but set the turbo states to 4.2/4.2/4.2/4.1).