Important: 10.7.4 and Sandy Bridge CPU PM Temporary Fix

[MacMan]

There is an issue with running OS X 10.7.4 on some Sandy Bridge CPUs. Apple has upgraded the power management kexts and it is affecting performance. What you will happen is the CPU will be stuck at a 16x multiplier and limiting it to run at 1.6 GHz.

An easy way to check if you've been affected is run Geekbench- if your scores are cut in half, you're affected.

So what can you do? If you can hold off on upgrading wait until we have a complete solution. Otherwise the only solution is to manually edit org.chameleon.Boot.plist and do the following.

1. Open your /Extra/org.chameleon.Boot.plist with /Applications/TextEdit
2. Delete these 2 lines if they exist:

	<key>GeneratePStates</key>
	<string>Yes</string>

3. Add these 2 lines if they don't exist.

	<key>DropSSDT</key>
	<string>Yes</string>

4. Save the plist
5. Reboot.

We will be adding an option in MultiBeast to do this soon if you don't want to edit the file yourself.

Please add any relevant testing information to this thread. Thanks.

UPDATE:

Upon further testing we have found that a proper SSDT can solve this issue. We are working on creating a generic SSDT for any Sandy Bridge CPU and a tool to edit your org.chameleon.boot.plist with the proper settings. This SSDT would be used in addition to the DSDT you are using.

Also I have found on Gigabyte Z68 boards you MUST have the following setting in the BIOS:

Real-Time Ratio Changes in OS: Disabled
CPU EIST Function: Enabled (if available)

If not you will still get the p-state stepper error at boot and CPU ratio locked at 16.


UPDATE 2:

10.7.4 Power Management and Sandy Bridge CPUs
http://tonymacx86.blogspot.com/2012/05/ ... ridge.html

 

[SStreet]

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

Macman,

I want to add that this problem also effect non-K processors.

I also can confirm that the above workaround does also work.


Also a curious change:
Under 10.7.4:

AppleIntelCPUPowerManagement: Turbo Ratios 1234

Yet, 10.7.3:

AppleIntelCPUPowerManagement: Turbo Ratios 4444

Note: No BIOS settings have changed... just the software update.

 

[Mate94]

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

Dropping the "SSDT" must means something a bit more. Is there anything more to know about this? I am curious.

 

[Vendetta]

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

Macman,

I want to add that this problem also effect non-K processors.

I also can confirm that the above workaround does also work.

Can you elaborate on how you discovered your issue? Are you using MSRDumper to check pstates?

 

[MacMan]

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

Macman,

I want to add that this problem also effect non-K processors.

We have confirmation via MSRDumper that it didn't effect a GA-Z68MX-UD2H-B3 i5-2400 or an GA-H67N-USB3 i3-2105.

 

[kroat999]

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

 

[tonymacx86]

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.

 

[SStreet]

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

Can you elaborate on how you discovered your issue? Are you using MSRDumper to check pstates?

HWMonitor.app (included as part of Multibeast 4.4), multiplier was stuck at 16x. [maxes at 35 with XMP Profile enabled.

Board: Gigabyte GA-Z68A-D3H-B3 (BIOS: F13)

I updated bios week or so back -- that combined with the 'test' DSDT for this board fixed the sleep/wake issues I was having- even with the DSDT from the previous BIOS.

 

[iPodize]

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

I was just about to buy an i5-2500K, should I, or should I get an Ivy CPU, or an i5-2500? And what does dropping SSDT do besides fixing the problem?

 

[MacMan]

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

From MSRDumper on that i5-2400 system:

5/9/12 6:17:32.000 PM kernel: MSRDumper PStatesReached: 16 17 18 19 20 32 33
5/9/12 6:17:32.000 PM kernel: MSRDumper CoreMulti(16)
5/9/12 6:17:32.000 PM kernel: MSRDumper PStatesReached: 16 17 18 19 20 32 33
5/9/12 6:17:33.000 PM kernel: MSRDumper CoreMulti(16)
5/9/12 6:17:33.000 PM kernel: MSRDumper PStatesReached: 16 17 18 19 20 32 33
5/9/12 6:17:33.000 PM kernel: MSRDumper CoreMulti(16)
5/9/12 6:17:33.000 PM kernel: MSRDumper PStatesReached: 16 17 18 19 20 32 33