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21 Posts

04-30-2010

California

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i720QM CPU Throttling Issue

2010-08-16, 17:57 PM

I have a 1.6Ghz rated i7 laptop.  I noticed that when I pull the AC power on my laptop and leave it running on battery alone, my CPU unexpectedly throttles down to 1.46Ghz.  This also happens if I shut down the machine and start up on battery alone.  However, if I restart the laptop with only battery as a power source, the CPU runs at the expected 1.60Ghz.  Is anyone else experiencing this problem?  I am using the Intel Processor Identification Utility to measure CPU speed.  It seems to me the throttling down that occurs on pulling the AC power or on starting with battery alone is an electrical design flaw.

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288 Posts

04-20-2010

Ottawa

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Re: CPU Throttling Issue

2010-08-16, 18:49 PM
There are a number of settings in the power manager, and also in the BIOS related to performance with power versus battery -- are you sure you have those all configured for maximum performance? If you have any of them set for "balanced" for example, you'll see what you are experiencing.
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21 Posts

04-30-2010

California

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Re: CPU Throttling Issue

2010-08-17, 16:03 PM

Thanks Don. I have tried extensively to set power settings in a way that makes my laptop stay at 1.6Ghz but this doesn't work.  I don't think power settings would account for the throttling when I remove the AC power, since when I do a restart the CPU goes back up to 1.6Ghz.. 

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1600 Posts

05-29-2010

Singapore

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Re: i720QM CPU Throttling Issue

2010-08-18, 16:21 PM

Most likely, it is because of Enhanced Intel Speedstep Technology

I use another software to test the clock speed of my i7 720QM,
when I was just doing some word editing, it is just running on ~930MHz - 1GHz 
when it is on mid-load, it is running at around 1.4 - 1.6GHz
when it's on full-load, it will rise all the way up to 2.8GHz (max) Thanks to Intel Turbo Boost.

 

The clock speed will not be constant as it will change accordingly to how much power the software needs.

 

Try disabling Enhanced Intel Speedstep Technology and CPU Power Management and set anything related to CPU for Maximum Performance from the BIOS if you really want your CPU to constantly run @ 1.6GHz or higher, but battery life will be decreased.

 

 

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21 Posts

04-30-2010

California

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Re: i720QM CPU Throttling Issue

2010-08-18, 23:19 PM

Configuration settings don't explain why when I run on battery only and restart my machine it runs at 1.6Ghz and stays at that clock rate until I either shut down the machine and turn it back on or sleep and wake it (again, with BATTERY ONLY).  The machine runs at 1.4Ghz at all times except when I do a restart.  Clearly there is a bug in a system that does this. 

 

I currently have set my machine to the "Maximum Performance" setting and the problem persists. On my machine, SpeedStep doesn't activate if I am running on battery only.

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250 Posts

04-18-2010

USA

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Re: i720QM CPU Throttling Issue

2010-08-18, 23:35 PM

Not sure if this helps ...

 

http://forum.notebookreview.com/lenovo-ibm/480518-facts-turbo-boost.html

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