X220 cpu throttling problem [ Editado ]

[vinuneuro]

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.

[Roger99]

I've not heard of this before. Do you have any references?

[SR45]

It's happening to many of us and reported on the other Notebookreview.com forum linked below.

http://forum.notebookreview.com/lenovo-ibm/

Thread on this subject but other threads have mentiond this as well

http://forum.notebookreview.com/lenovo-ibm/576364-thinkpad-sandy-bridge-cpu-throttling-problem.html

[ColonelONeill]

The battery is plugged in, right?

[vinuneuro]

Yes, this is happening while the machine is plugged in. That's troubling part. When on battery, this behavior is desired.

The effect of this is two fold. My movies aren't on the ssd, they're on the 7mm hdd. It is throttling up/down to 797mhz when 720p and 1080p movies are playing. This is purely cpu related.

The second aspect is ssd related. Other users got the same result as I did for the same ssd (and it's surely affecting all ssd's). It's not some trivial difference limited to benchmarks, 20% on random reads and 40% on random writes is very significant. There's a whole Anandtech article (or series of them) on why random performance is the most important aspect in the usability of an ssd.

Here's my thing with this issue. Why can't this throttling behavior just be eliminated while the machine is plugged in. There's no need for power saving in that condition. In Power Manager and the BIOS, there's a global setting to turn CPU Power Management off. All we need is to be able to control this separately depending Battery or AC power.

[andyP Retired SuperMod]

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vinuneuro wrote:
Yes, this is happening while the machine is plugged in. That's troubling part. When on battery, this behavior is desired.

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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.

[vinuneuro]

Hi, yes both the battery and power cord are plugged in.

[jyeah]

http://forums.lenovo.com/t5/X-Series-Tablet-ThinkPad-Laptops/Buyer-Beware-Your-power-adapter-may-be-...

Please refer to this thread.

[vinuneuro]

It's happening on my spare 90W adapter as well.

[thecrafter]

This is happening to me too. When plugged in or on battery, it keeps switching between 2GHz and 800MHz (profile set to max performance)