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34 Posts

02-19-2014

Nederland

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  • Message 11 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-06, 19:07 PM
Thanks for the hint, it's worth a shot.
Do you use the Windows 8.1 power plans?
I tried installing Energy Manager 8.0.2.43 but that doesn't seem to do anything other than installing the acpi driver.
Should it also have a utility?
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34 Posts

02-19-2014

Nederland

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  • Message 12 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-06, 19:24 PM
Tried it, but it does not help.
On cold boot you can see the CPU multiplier drop from 12 to 8 and then it stays there. The CPU does not clock up.
Reboot and the problem is gone.
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2651 Posts

03-21-2012

Malaysia

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  • Message 13 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-07, 3:26 AM

Hi all,

thanks for posting and to those that have just registered, I'd like to welcome you to the community. I was reading through this thread and found it to be similar to the case I was working a while back. Only difference was the CPu was getting stuck after a specific time of use and not upon boot as reported here. 

 

Judging from what has been reported here I'd like to bring this up with our teams internally. However I'd like some details from you. Could you PM(Private Message) me, the following details below.

 

Serial number (Mandatory) :

 

BIOS version :

 

OS :

 

OS type (Eg. Preload, Fresh Install or upgrade) : 

 

Full Name :

Phone:

Location :

Email :

 

Hope to hear back regards

 

 

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8 Posts

03-06-2014

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  • Message 14 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-07, 7:09 AM

thank you for your concern, i ve sended the info. 

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2651 Posts

03-21-2012

Malaysia

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  • Message 15 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-06, 18:40 PM
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34 Posts

02-19-2014

Nederland

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  • Message 16 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-07, 7:54 AM

Hi NINE,

 

thanks for picking this up.

I'll send you the required info.

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4 Posts

01-18-2014

Austria

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  • Message 17 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-07, 18:17 PM

I have also sent you the required information

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236 Posts

05-09-2010

Cochrane

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  • Message 18 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-07, 18:57 PM

Intel uses Model Specific Register (MSR) 0x199 to control the maximum multiplier in all of their CPUs.  If this register accidentally gets set to 8, this will limit your CPU to approximately 798 MHz (8 x 99.77 MHz).  It should not be happening but it is a common bug.  This can happen randomly when switching profiles or changing the power source while in stand by or hibernate mode. 

 

The easiest way to test for this is to run CPU-Z, click on the About tab and click on the Save Report (.TXT) button.

 

In this file it will show you the value for register 0x199 for each thread.  A 4700MQ has 4 cores + hyper threading so the CPUZ log file should show a value for this register for each of the 8 threads.  Have a look at this value when your CPU is running correctly at its full rated speed.  If someone can post the value of this same register when they are having problems, I think it will be pretty obvious.  This value should be consistent across all 8 threads.

 

If this is the problem, for a temporary fix, try running ThrottleStop.  Click on Set Multiplier and set that to the maximum value.  This will write an appropriate value to MSR 0x199 so the CPU can resume running at its full rated speed.  No need to reboot after you do this.

 

If you are using Linux, you can write the appropriate value to this MSR directly.

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34 Posts

02-19-2014

Nederland

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  • Message 19 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-07, 20:00 PM

Hi,

 

thanks for the input. This does seems to describe the problem.

Normaly my notebook is on the carger and when I use, I unplug it and boot to Windows and see the issue every time.

Today I discovered booting when connected to the power supply will not show the issue.

I've made a dump with and without the issue and this is what it shows:

 

Running Prime95 single worker (stuck on x8):

MSR 0x000001990x000000000x00000800 (for every thread)

 

Running Prime95 single worker (x30, no x31 somehow):

MSR 0x000001990x000000000x00001F00  (for every thread)

 

 

You might be on to something here.

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236 Posts

05-09-2010

Cochrane

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  • Message 20 of 419

Re: Lenovo Z510 CPU stuck at 0.77GHz

2014-03-07, 20:33 PM

Those numbers are in hexadecimal. 

 

0x1F = 31 decimal

 

Bingo

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