05-06-2011 07:56 AM - edited 05-06-2011 08:05 AM
We've now confirmed that the X220 cpu is constantly throttling down to it's lowest state even when a max performance profile is used, even while plugged in. This very likely affects the T420/s / T520 too and maybe even W520's. The direct effect is reduced random write (the most important) ssd (and maybe even hdd) speeds, but who knows what else it is affecting. I see it throttling in cpu-z even while playing music and youtube videos with dxva off.
This is not a new issue and not unique to Thinkpads; it's been around a few Intel chipset generations. What is unique to Sandy Bridge Thinkpad however is that the Windows tweaks that take care of it in other notebooks isn't working here. The only way I've found to stop the throttling is to either disable Intel Speedstep or CPU Power Management in the BIOS. The first is a drastic move since it locks the processor at high speed/voltage and the power consumption drawbacks are obvious with that. Disabling CPU Power Management is more subtle but it also has (less) significant effect on battery life. This is the sure fix for throttling since it uses the speed you want without constantly dropping it down to the lowest state, however while on battery even at the lowest active cpu state it uses at least 2.5-3W more than when it's enabled.
So the solution looks like it needs to come in the form of a BIOS update. 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.
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05-06-2011 08:37 AM - edited 05-06-2011 08:39 AM
It's happening to many of us and reported on the other Notebookreview.com forum linked below.
Thread on this subject but other threads have mentiond this as well
05-06-2011 11:09 AM
05-06-2011 12:16 PM
Yes, this is happening while the machine is plugged in. That's troubling part. When on battery, this behavior is desired.
ColonelONeill's question was rather if the battery was plugged in as well as the power cord, meaning on mains power and with the battery inserted.
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