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X220 CPU throttles back to low clock rate while on AC with 65W adapter - prior to BIOS 1.21

by ‎09-21-2011 03:43 PM - edited ‎09-21-2011 03:44 PM (2,358 Views)


 X220 CPU clock rates may  throttling down to lowest state even when a max performance profile is used, even while plugged in when using the 65W adapter.  Unlike other power controls in Power Manager / BIOS, CPU Power Management (and Speedstep) can only be turned on/off globally, not separately by power source.


X220 ThinkPads using the 65W adapter and BIOS versions prior to 1.21 could exhibit these symptoms.

No throttling was evident when using 90W AC adapters.



The cumulative fix to address the semi-perma throttling described above is contained in BIOS 1.21 and later - see links below.  This also includes the fixes for the perma-throttling symptoms previously resolved in version 1.19.



BIOS 1.21 for X220


BIOS Utility here

BIOS text here



BIOS ISO text here


  Version 1.21

[Important updates]

[New functions or enhancements]
- Improved system performance when heavy program is executed with 65W AC adapter.
- Improved system boots time.
- Disabled keyboarding while the lid was closed to avoid unexpected key input
  when the computer was held with the lid closed.

[Problem fixes]
- Fixed an issue where the computer might not be booted from bootloader program.
- Fixed an issue where a 1820 error might occur at power-on when the external
  fingerprint reader device was attached to the computer while the integrated
  fingerprint reader was disabled in the ThinkPad Setup.
- Fixed an issue where the computer might fail to boot when connected the
  Smartphone with the USB port.
- Improved cooling fan noise.
- Corrected spelling mistakes in BIOS setup menu.


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What happens to the throttling when the battery ceases to function and doesn't provide extra power to the laptop? Will the laptop become permanently throttled down?


I've got a throttled-down X220T with a broken battery, newest BIOS (1.39) and a 65W adapter provided with the laptop.


Sorry for writing this on a non-tablet thread, but I thought that either this problem applies to both models, or if there's no problem with X220, it can be solved on the X220T, too.