Important: 10.7.4 and Sandy Bridge CPU PM Temporary Fix

[ergman]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

question:
what does actually happened removing those 2 strings?
other question:
would it be better of staying on 10.7.3 ??

 

[chorner]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

"I wonder if rolling back to the old AppleIntelCPUPowerManagement would fix it as a workaround for now..." -- See Tony's reply below. Seems it's more than just that driver.

 

[genzai]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

Well my situation was even worse. I got kernel panics on startup after the update.
Here is the panic call:
IMG_0805.jpg

Possibly relevant info is i am using the GA-Z68MX-UD2H-B3, Bios F12, EHCI-Sleep fixed dsdt, 16GB ram, i7 2600K
I also use a RAID0 system volume (2x128GB SSD). and i use turbo mode overclocking.
I tried disabling the overclock and still got the panic.

Finally booted from a recovery drive and made the boot.plist changes from this thread. Now it boots fine and P-states are still working according to SMC Monitor.

I, like others, am wondering what other repercussions there are from using DropSSDT.

Many thanks,
g\

 

[sfroom]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

What effect does changing DropSSDT and GeneratePStates have on the system?

I'm also very curious as to what DropSSDT and deleting GeneratePStates has on the system.

Would a better solution, as has been suggested, be to roll back the Intelcpupowermanagement kext?

Thanks.

 

[andariego76]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

It afects non K CPUs also i was lokd at 1.6 Ghz

Mainboard: ga-z68xp-ud4

CPU: i7-2600

Checkd with SMC Monitor and Cinebench

Workaroud "Drop SSDT" Works

Thanks for the feedback- would be interested in anyone's test results- keep them coming.

Hi Tony! are the Ivy cpu's affected? I have an i7-3770K and Gigabyte Z77x-UD5H

 

[tonymacx86]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

Rolling back IntelCPUPowerManagement does not work- things are too different with the new kernel. This workaround will give you access to full power and minimal p-states in 10.7.4 as a temporary fix.

For example a i5-2500K would give 16x and 34x autoswitching power states and achieves full performance benchmarks.

 

[rockstarjoe]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

I have an i7-2700k but I'm scared to mess things up. Anyone else with this processor?

 

[wfj]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

Have a test bench setup with MSI Z77a-GD55 and i5 2500k with a modded BIOS. Never had the generate p-states command in boot.plist but added the drop ssdt. Before update got 6 p-states and after only 2 (16 and 35). Not sure why the top end is 35 as I would expect it to be 34 with this cpu. Definitely locked at 16 without the drop ssdt fix.

Edit - Oops...had i5 2550k installed not 2500k.

 

[sfroom]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

Rolling back IntelCPUPowerManagement does not work- things are too different with the new kernel. This workaround will give you access to full power and minimal p-states in 10.7.4 as a temporary fix.

For example a i5-2500K would give 16x and 34x autoswitching power states and achieves full performance benchmarks.

P-states are essentially multipliers between 16 and 34x? i.e. if we disable generate p-states, the processor will idle in a low power state, but will only basically have two modes "idle" and "full power"?

What does drop SSDT do?

 

[tonymacx86]

Re: IMPORTANT: 10.7.4 and Unlocked Sandy Bridge CPUs [TEMP FIX]

We're working on this as we speak- and we don't have all the answers. But if you list all of your testing results with 10.7.4 here, we may be able to have a general discussion on how to fix it.