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Is it bad to use Null CPU Management . kext


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#1
Crabhunter

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Title says it all, I need the NullCPUkext to boot my system.
Does that mean my system is not running as well as it could?
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#2
mnfesq

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Right, it is not using native CPU power management. For my laptop, using NullCPUPowerManagement breaks sleep.

#3
3.14r2

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The above thing prevents CPU power management function to load when system starts and therefore prevents KP for unsupported CPUs. In other words your CPU is working on its max performance (max clock speed - no speedstep) regardles of the current load. More heat generated, more power consumed, bigger power bills.

Original OS X kernel is designed to work with limited number of Intel CPUs, so most CPUs (not all though) not present in any Macs, may require the power management to be blocked.

Some other problems are also possible.

I've had a system with non compatible Intel CPUs and power management have been disabled all the time. System was perfectly working...

#4
buoo

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Right, it is not using native CPU power management. For my laptop, using NullCPUPowerManagement breaks sleep.


...but in certain situations, if you are forced to use it, you can use sleepenaler to get the sleep working. ;)

#5
Crabhunter

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It seems to be running fine, I have to use sleepenabler and I needed a dsdt edit to be able to use it.
I'm assuming battery life will be shorter.
My cpu is an i3 3217u 1.8ghz although in about this mac is says 1.7ghz
How can I tell what speed it is actually running at?
Mike

#6
nyolc8

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On a laptop, it's really recommended to use native power management... because of the battery life and temps. You can change the ghz value in about this mac by editing smbios.plist's "smmaximalclock" value.

#7
rayman121985

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I just installed an SSDT that supports my i7 Ivy Bridge does this mean I should remove the NULLCPU kext now? Thanks...



#8
AdriHD

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Indeed it would be a bad idea. Part of the management system is to control fan speeds etc... On regular macs, the SMC relies on the Proc-Management to ensure that if it's overheating it either speeds up the fans or slows down the processor (via FSB).

 

On top of that, when you're not using as much processing power as you need, it drops the various core essentials (voltages, speeds etc...) to conserve power i.e. handy in laptops. When the power is needed it then allocates and distributes the tasks accordingly across the cores until the maximum threshold is reached.

 

A good example is this intel's Power Gadget output with Management on (on my Mac Pro). As you can see it was idling away, then i did a /usr/libexec/locate.updatedb to put some pressure on the processor (as you cans ee, it dynamically changes:

 

25aon80.png

 

Furthermore, if you're a developer, you can get interesting information from the underlying processor management subsystem.

 

Hope my input helps.

 

Cheers,

 

AdriHD



#9
rayman121985

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Thank you I just did a fresh reinstall of OSX Mountain Lion...How can I tell if my power management is working properly? Is there a way to test if the CPU is running natively?

 

 

THANKS!



#10
nutric

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Hi there!

 

Put the HWMonitor app in your app folder. Link:

 

https://www.dropbox....vhwz/-JJuKI9zXs

 

Use Kext Utility to add the IntelCPUMonitor.kext. Link:

 

https://www.dropbox....c7bl/gk8sOEW_us

 

Add HWMonitor to your login items and reboot. You should see the HWMonitor icon in the menubar. Click on it and there will be the temperatures and multiplier :) 







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