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Fanfold Paper
Posts: 1
Registered: ‎10-19-2010
Location: Melbourne Australia
Message 1 of 4 (2,319 Views)

System choking up when AC power is connected




I have a Lenovo Thinkpad edge 13 with,

windows 7 32bit,

intel i3 cpu,

u7300 @ 1.3ghz,

4gb ram,

SSD primary.


Occasionally the machine slows down to the point where it's unusable, the mouse pointer also stutters and you can see the gui rendering slowly. 


If I can get task manager process list or sysinternals process explorer open then whichever process has focus seems to be using cpu flat out 50% (100% of 1 core), so when viewing taskmgr or procexp they appear to be flat out on the cpu.


I have now noticed that there is a relationship between this and connectiopn of AC power. If I disconnect AC while the system is choking, the system will suddenly speed up and work normally again.  I have never noticed this happening while the system is running on battery.  Often only a short time after connecting AC, this problem will occur.


I suspect that this is either a kernel mode power management issue or an issue with intel cpu power modes.


I have tried selecting different modes (maximum performance, maximum battery life, video playback etc) in the lenovo power management console but this has not made a difference to the problem.


Someone please help me as this is beyond the scope of my troubleshooting abilities.


...Btw also I have noticed that full screen video appears to be dropping a lot of frames which seems crazy in 2010 on a machine like this, that may or may not be related so I thought I would mention it. Also I need to improve that, but that is a secondary issue.









What's DOS?
Posts: 1
Registered: ‎01-19-2011
Message 2 of 4 (2,193 Views)

Re: System choking up when AC power is connected

I have ThinkPad Edge 13'' Intel u7300 and I have similar problem - my system is running really slow when laptop is charging. When I unplug AC system is running normally. The same model is for both Windows and Ubuntu OS.
My question is - does the AC adapter is recognised in proper way?
Almost the same problem was with Dell laptops.
Community Moderator
Posts: 3,765
Registered: ‎01-21-2010
Location: US
Message 3 of 4 (2,176 Views)

Re: System choking up when AC power is connected


run system update and see if your drivers are up to date, especially the bios.  it should be in programs, thinkvantage.  if you don't have it download it from the link and run it.  a lot of these laggy problems and slow internet are caused by an outdated bios.

Paper Tape
Posts: 2
Registered: ‎09-02-2010
Location: Finland
Message 4 of 4 (1,799 Views)

Re: System choking up when AC power is connected

Hello, I had the same annoying problem of cpu freezing on ac power. Today I think I finally solved it; It was the factory installed software "Lenovo ThinkVantage Toolbox powered by PC Doctor" that caused the choking. Uninstalled it, and now my Edge 13 is allright again. This was not visible in applications or processes in task manager, the cpus just were 100% all the time.

I really am amazed by this, and once again discovered the fact, that all factory installed software should always be removed when buying a new PC. All those bundle-software seems always be just crap, even if the machine is Lenovo!


Cheers, and hope this helps someone. AltGr

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