T520 Bios update cripples 2720QM cpu
Posted: Tue May 24, 2011 5:53 pm
After I updated T520 to BIOS version 1.25, the Core i7 2720QM processor would no longer use the Turbo Boost Technology to throttle individual cores above 2.2GHz! Previously the cores would throttle up to 3.3GHz, depending on the application, temperature, power management settings, etc.
On a hunch, I reverted back to the previous BIOS (1.22) and the processor again throttles up to 3.3GHz.
Clearly there is problem with the 1.25 BIOS that cripples the processor. Hopefully Lenovo will address this issue in next BIOS update, but for now I recommend people stay away from version 1.25.
If you want to verify this for yourself, first make sure you set the System Performance setting to "Maximum Turbo" for AC and/or battery power (I believe that is the default setting for AC) in the Lenovo Power Manager. Then you can run CPU-Z to view the instantaneous processor speeds, and see the speed change under various loads. Under AC power with Maximum Turbo set, the CPU should be able to throttle up to 3.3GHz. To place the CPU under maximum load for testing, you can use Prime95.
Can anybody with a different processor in their T520 also verify that the 1.25 BIOS cripples the processor? I'd expect that Turbo Boost is disabled for any processor with that BIOS, but I'd like to be sure. Lenovo still hasn't posted an update that corrects the problem.
Mike
On a hunch, I reverted back to the previous BIOS (1.22) and the processor again throttles up to 3.3GHz.
Clearly there is problem with the 1.25 BIOS that cripples the processor. Hopefully Lenovo will address this issue in next BIOS update, but for now I recommend people stay away from version 1.25.
If you want to verify this for yourself, first make sure you set the System Performance setting to "Maximum Turbo" for AC and/or battery power (I believe that is the default setting for AC) in the Lenovo Power Manager. Then you can run CPU-Z to view the instantaneous processor speeds, and see the speed change under various loads. Under AC power with Maximum Turbo set, the CPU should be able to throttle up to 3.3GHz. To place the CPU under maximum load for testing, you can use Prime95.
Can anybody with a different processor in their T520 also verify that the 1.25 BIOS cripples the processor? I'd expect that Turbo Boost is disabled for any processor with that BIOS, but I'd like to be sure. Lenovo still hasn't posted an update that corrects the problem.
Mike
Lenovo Tech Support > #@$^#^#*#,, GRRR!!