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How To Test for SpeedStep on Socket 1155 CPUs using MSRDumper

MacMan

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msrdumper.png
The best way to test for SpeedStep working on Socket 1155 CPUs is by using MSRDumper. This is a kernel extension developed by flAked and DHP designed for reading the Machine Specific Register (MSR) that contains the current P-state and logging it. The downside to this kext is that if you continue to run it for a long time it will fill up your kernel log file. When the log file reaches 1000K it's rolled over and is saved off and another log file is created. Eventually you could fill up a significant amount of disk space. Based on that I will document how to run it on demand and how to unload.

The first thing you need to do is change ownership of the kext. In Terminal you need to go to the directory that contains the unzipped attachment and run the following command:
Code:
sudo chown -R 0:0 MSRDumper.kext

Then when you want to run MSRDumper type the following command in Terminal in the directory that contains MSRDumper:
Code:
sudo kextload MSRDumper.kext

Then in the Console application click on kernel.log and you will see entries like the following:
Code:
May 12 20:30:02 MacBook-Pro kernel[0]: MSRDumper CoreMulti(31) 
May 12 20:30:02 MacBook-Pro kernel[0]: MSRDumper PStatesReached: 8 11 15 19 23 25 26 27 28 29 30 31 33 34 
May 12 20:30:02 MacBook-Pro kernel[0]: MSRDumper CoreMulti(31) 
May 12 20:30:02 MacBook-Pro kernel[0]: MSRDumper PStatesReached: 8 11 15 19 23 25 26 27 28 29 30 31 33 34 
 
Note: These log entries are from my Early 2011 MacBook Pro.

MSRDumper CoreMulti(31) shows that the current P-state is 31 and
MSRDumper PStatesReached: 8 11 15 19 23 25 26 27 28 29 30 31 33 34 shows all the P-states seen since the kext was loaded.

Be patient when first running MSRDumper as it takes awhile to see multiple P-states. You might need to run some programs to change states.

To stop MSRDumper run the following command in Terminal in the same directory as the kext is located:
Code:
sudo kextunload MSRDumper.kext

Alternately, you can test that SpeedStep is working on your system by installing FakeSMC Motherboard plugins, and HWMonitor application. Both are available in MultiBeast.

Related:
Original Thread - July 2011
 

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As I have found out only recently, the range of P-states that your CPU will be set to depends on the product family set in your SMbios.plist. For instance, my i7 3770 has only 16 34 when faked to be a MacBook Pro Retina, but 16 17 18 20 33 34 37 when set to a MacPro3,1. As an iMac it's 16 33 34 37.

So solely relying on MSRDumper can be misleading, because the results are not what your CPU + mainboard actually support.

Actually, from the product family Mac OS will derive which chipset your mainboard it supposed to have, and set the "appropriate" range of P-states that your CPU is supposed to support with your chipset (i.e. Apple-manufactured mainboard).
 

tonymacx86

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Article: How To Test for SpeedStep on Socket 1155 CPUs using MSRDumper

Will be interesting to see what happens to these readings when using one of the new Ivy Bridge iMac defs if/when they arrive this month. :thumbup:

They should have the i7-3770 as the high end 27" model.
 
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6 months ago i had some bad experiences using fakesmc plugins giving me kernel panics. After reading this i gave it a try again to see if my 2500k cpu is running normally and now i can't even get into safe mode anymore and restore my system. I will never ever touch those plugins again in my life, they ruined my whole system for the second time now..

edit: fixed it by deleting OemSmbios plugin. HWMonitor is working now and the steps i have on my 2500k are 16,17,18,19,20,21,34,35,36,37 using mac pro 3.1
 
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My i5 3570K on H77ITX-A-E:

MacPro 3,1: 16, 17, 18, 19, 20, 36, 37, 38
MacMini: 16, 23, 31, 36, 37, 38
iMac, MacPro 5,1: 16, 36, 37, 38

I think 36, 37, 38 maximum (with turboboost), so speedstep not working in iMac and MacPro 5,1. MacPro 3,1 so far give best result.

This is using rl's script to generate SSDT.aml for i5 3570K, without OC
 
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Article: How To Test for SpeedStep on Socket 1155 CPUs using MSRDumper

6 months ago i had some bad experiences using fakesmc plugins giving me kernel panics. After reading this i gave it a try again to see if my 2500k cpu is running normally and now i can't even get into safe mode anymore and restore my system. I will never ever touch those plugins again in my life, they ruined my whole system for the second time now..

edit: fixed it by deleting OemSmbios plugin. HWMonitor is working now and the steps i have on my 2500k are 16,17,18,19,20,21,34,35,36,37 using mac pro 3.1


I had the same issue with HW monitor, but only afgter uping to 10.8.2 from Lion, I too had to delete the OemSmbios plugin.
And, I also have a 2500K, but my Pstates are only 16-17-18-19-20-37 using MC Pro 3.1 as well.

Am i missing something?
I'm running UEFI bios on a Z68MA-D2H-B3 Motherboard.
 
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MacMan, what is your CPU setting and what smbios are you using? It's incredible to see you are getting that many speedsteps. I am only getting 8. mine is i5-2500k oc'd 39 in turbo boost stock clk.
 
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