Thinkpad Sandy Bridge cpu throttling problem

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.

 

are you actually noticing the speed differences outside of benchmarks or is this something you're only seeing affect benchmark numbers?   if it's outside of benchmarks, what tasks are you performing where this is most apparent?

 

maybe this is why the photoshop benchmark i am doing is soooooo slow!

 

It's not very scientific, but I use the Muppets Studio channel on Youtube to test CPU usage, as well as Flash acceleration of GPUs, as it goes to 1080p and has funny content.

YouTube - MuppetsStudio's Channel

I just tested using CPU-Z, and my CPU runs all resolutions through 720p fine at 800MHz. When I switch to 1080p, it ramps up to 2.5GHz and stays there until video playback is complete, and then quickly drops back to 800MHz.

While not scientific, it seems like normal behavior to me. The Sandy Bridge CPU is Intel's most efficient CPU to date.

I know when I play a game of Torchlight that I'm stressing things --air from the exhaust gets plenty hot (though the system never gets unstable). I'm quite sure the CPU is ramping up there too, though I'd have to run it windowed to tell. I'll see if I can do that and let you know.

Note that I haven't really seen my CPU go into Turbo mode; but I'm not sure I stress it hard enough to do so. Also, my experience is that of one person; it could be that not everyone is experiencing issues.

 

I noticed some random stuttering (not drastic) while playing movies that I never had in the T400. I didn't know what it was when I first noticed it, but just checked and sure enough the cpu is constantly dropping to it's lowest speed even while playing a 720p or 1080p movie.

Pretty much any program that relies on ssd random write speed will be significantly affected as well as program installation performance; and this is only the hard drive aspect of this. It's not an insignificant ssd performance hit that's limited to benchmarks, it's over 40% slower in random write (the most important).

This is behavior is fine (and wanted) on battery, but there's no reason to have this happen while plugged in.

 

Still waiting for my x220 - will come in two weeks or less, so i'm quite interested in the problem.
Could you be so kind to add some pics (screenshots) with throttling (CPU-Z), current temps (HWInfo32) and workload (Task manager)? Is it just erratic system behaviour or a consequense of overheating etc.?
Can you launch some CPU test (wprime or smth else) and see how it goes?
By the way, according to notebookcheck.net reviews of T420 and T520, throttling doesn't take place there at all. But these models have much more space to fill cooling system in.

 

Okay. Just for fun, I ran Torchlight (for those that don't know it, an adventure game much like Diablo II but with Warcraft-III level graphics) in a 1280x720 window.

Doing nothing really intensive, just walking around for a minute or so with no combat, I could get clock-speed up to 2.99GHz. I did it a second time to confirm with both CPU-Z and Task Manager open. While CPU usage was relatively low, around 16-17%, it was clear from the graphs that only one core was in use and had been cranked up.

I don't think the throttling is happening with my system at this time. It's possible I'm not affected though, and others here are, or my tests just aren't strenuous enough or long enough.

 

shouldn't it be going to 3.2ghz?

and unfortunately, my photoshop benchmark did not improve after changing the BIOS settings...still slow as a dog.

 

Vin, for clarification, where do you have the movie stored that you're playing back? Is this an issue you believe comes into play only when the SSD and the CPU are stressed simultaneously?

I'm asking so I can get a better idea, and potentially replicate your issue. I use my SSD mostly for reads, and as little for writes as possible, so maybe I'm just not replicating your conditions well enough. The game I played is on my D: drive, for example, and most movie files I have are stored on my Windows Home Server, so I stream them rather than having them directly on-disk.

So far, there's nothing my T400 did that my T420 can't do faster, so I'd be interested in seeing if I could replicate the video stutter.

 

On my T420s I am getting best performance with the following settings in Power Manager:

System Performance: Maximum Turbo
CPU Deeper Sleep: Disabled
Optimize Fan Control to: Maximize Performance

On these settings my i5-2520M appears to maintain 3GHz with all cores loaded. It is giving Cinebench10 32bit scores of: single CPU = 4076, multi CPU = 8891 (compare with other scores here). If I change the fan control setting to Balanced or Reduced Noise then the CPU performance will be reduced. And the T420s should have a cooling system also able to handle a dedicated GPU.

One observation is that when Maximum Turbo is enabled, HWiNFO32 shows a CPU speed consistently in the range of 3 to 3.2GHz even when the CPU is idling.

Notwithstanding the above, it comes as no surprise to me that the CPU in the X220 is throttling. I see the same happening on a Toshiba R700. It may be informative to check what HWiNFO32 reports as the maximum CPU power. The i5-520M in the Toshiba R700 never gets above about 17W. Running the Cinebench benchmark (and the other benchmarks listed by notebookcheck) will also provide an indication of performance reduction.

John

PS: The alternative to accepting throttling when using full-power CPUs in a chassis with cooling constraints is to use one of the lower power CPUs with a lower thermal rating. However, those cost more to buy and probably perform no better than a throttled full-power CPU.

 

Not necessarily. I believe there are several steps as clock-speed ramps up. The system ought to go to 3.2GHz if it needs it, but may not ramp all of the way there if it does not. I don't think I ever stressed the CPU hard enough, since both cores could probably handle this easily.
The 2520M can ramp up to 3GHz on two cores, and 3.2GHz on one, according to Notebookcheck.

There is one other variable in my case. I have Optimus graphics; a number of people here do not. In select cases, that might make my CPU usage different from someone using the Intel HD 3000.

 

It's disturbing. It really shouldn't be.

 

After playing with all of the BIOS settings, it never has gone to 3.2ghz, stays right at 2.5...I would think it would when doing intensive Photoshop work.

 

If it's staying at 2.5, it probably won't. That's the rated clockspeed. It will only exceed that if several conditions are met, one of which is that the other cores are running at low clockspeed. If you've got the bios settings so that it can't spin down the other cores, it also is set so you can't spin it up either.

(Note that's only one of several conditions. It may be that there are other issues at work.)

 

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. In the Muppets youtube link, it's throttling up and down on 720p as well as 1080p but no adverse effects here. This is purely cpu related.

The second aspect is ssd related. You got the same result as I did in the other thread. 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.

 

I just ran Prime95 torture test and at the same time I had Furmark running, and even though the CPU reached 92 degrees celcius, the computer did not throttle, it stayed at 2,7 GHZ in the 30 minutes I was testing it. The cpu is a I7 2620M and I have integrated graphic.

 

We already know that. If you run something that will really push the cpu hard it doesn't throttle. But if you're doing something more typical like 20-30% load, it does.

Solution to this very simple. Move CPU Power Management to the power plans/profiles instead of having it as a global setting in power manager.

 

Ok, I misunderstood that, I've never used SSD harddrives, they are to small for me, so I've never experienced any problems when the computer is throttling.

 

All,

The throttling issue on 65W AC was addressed via the BIOS update 1.21.
See this page:

BIOS Update Utility for Windows 7 (32-bit, 64-bit), Vista (32-bit, 64-bit), XP - ThinkPad