Inspiron 2650 - 1.8Ghz CPU 'stuck' at 1.2Ghz

Question

I have an Inspiron 2650 with 384 Mb RAM running WinXP Home.  Using the AC adapter, no matter what setting I use for power management, the CPU speed remains at 1.2Ghz.  There is no Enable/disable option in the BIOS for Speedstep in my implementation. I have used Speedswitch ( http://www.diefer.de/speedswitchxp/index.html) to monitor CPU speed and it always is at 1.2Ghz.  I have found, by accident, that if if I power up with the AC adapter, unplug the adapter, then replug it in, the CPU will run at 1.8 Ghz (though the computer Properties indicator states it is still at 1.2 Ghz).  This is a true 1.8Ghz as measured by Speedswitch and by several computation-intensive benchmarks.  Is there a better solution out there than this crude kludge?

ejn63 · Answer

This sounds like a mainboard problem - the system is defaulting to battery power unless you do something that jiggles the connector for the AC adapter.

The only real, long term fix is likely to be a replacement system board or a repair to the power jack (the boards are cheaper than the repair will be).

http://www.parts-people.com/index.php?action=item&id=1165&prevaction=search&previd=&prevstart=0

OlderGut · Answer

I don't think that a loose power adapter connection is the problem.  If the machine goes on standby with the kludged 1.8Ghz speed, it reverts to the 1.2Ghz mode upon reawakening.  Also, with the battery removed, the CPU is at 1.2Ghz.  This all occurs at the 'Max. performance' setting in power management.  Is this a goofed up BIOS situation?  A corrupted XP?

Balaji Ramanath · Answer

Clean out the air vents and the heat sink and other areas around the CPU thoroughly either by blowing on them or using a can of compressed air.  If the CPU is overheating because of dirt accumulation, then it will throttle down in speed to try to keep itself cool.

OlderGut · Answer

Blew out vents as suggested.  No change.  My 2650 will run all day at 1.8Ghz IF I startup on AC, pull the adapter plug to switch to battery and then reattach the adapter plug (with AC set for Max performance).  If this is not done, it will stay at 1.2Ghz all day.

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