update : 1-17-2012 a newer BIOS is out which includes these changes :
Looks like my Lenovo x220 got a new BIOS update!
official download link : 1.21 BIOS
CHANGES IN THIS RELEASE
[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.
– 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.
Reports so far are that it has improved WEI score (useless, I know, but some enjoy big numbers).
One user said : “As for the throttling fix. It appears to be working, when I run OCCT (the graphic/cpu stress) the cpu does not go to 800mhz, GPU is mostly at the 1300mhz turbo boost but fluctuates a little bit, so does the CPU but its mostly at 3.2-3.4ghz on both cores during the test. Before when running OCCT the CPU would drop to 800mhz.”
A lenovo staff member is quoted saying : ”
The version released yesterday is the version I was expecting later this month as I said yesterday. I didn’t realize, but the support team expedited it through. The internal testing shows good improvement on throttling with benchmarks and lab tests.”
Other users said they still experience the throttling though. Me personally, do not have the issue since BIOS 1.19
You can view the throttle issue thread here : link