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4 Posts

08-26-2017

CA

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T470 Heavy CPU Throttling on Battery

2017-08-26, 20:20 PM

Hi,

 

My CPU has been throttling down to 400 MHz when on battery. This does not necessarily happen on low battery - it sometimes happens when I have over 50% battery life left (albeit the removable battery is low), and sometimes when i have less than 25% battery life left. 

My temperatures appear to be good (according to Core Temp), usually around 40-50C. 

Has anyone encountered this problem before? All of my drivers are up to date according to Lenovo companion, and I have placed power settings in windows to High Performance, and changed the Intel Speedstep settings in the BIOS to max performance as well. 

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3 Posts

08-29-2017

US

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Re: T470 Heavy CPU Throttling on Battery

2017-08-29, 16:39 PM

 I assume you are running an HD20 variant of the T470.

 

Yes, we have the same problem with the HD20. On BOTH units that we own. It occurs whenver the external battery is in use: both laptops throttle to between 0.35 and 0.38 Ghz and stay there indefinitely. The problem is solved by unlocking (not even removing) the external battery. This forces the T470 to switch to its internal battery. The obvious downside to this suboptimal solution is it cuts your battery life in half in order to maintain decent CPU performance. Sometimes the CPU performs normally after reconnecting the external battery, but it is not a long term solution as the problem will resume after restarting the system.

 

Having gone through all the troubleshooting I could conceive of, I finally spoke to Lenovo and was told it could be a CPU/motherboard issue. There are now many forums about this problem. I think Lenovo may be hesistant to officially admit that this is a widespread problem with the HD20 as that could trigger a product recall. In any case, there are probably thousands of people out there who don't even realize thy're running faulty machines.

 

I sincerely hope Lenovo addresses this issue in a timely manner. I want to love my T470, but 0.38 Ghz top speed on a $1,700+ Core i7 laptop in 2017 is pushing the boundary of my patience.

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4 Posts

08-26-2017

CA

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Re: T470 Heavy CPU Throttling on Battery

2017-08-29, 16:49 PM

This is rediculous, if that's the case then I might have to return this computer. Fortunately I've only had it for two weeks, but it's going to be tough going without a computer for a while. It's a shame because I really do like the computer, but the low speed is unbearable. 

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3 Posts

08-29-2017

US

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  • Message 4 of 27

Re: T470 Heavy CPU Throttling on Battery

2017-08-29, 17:16 PM

I'm considering to send the machines in to Lenovo under the warranty. In the meantime, I'd take a half-functinoning T470 over most alternatives. Owned many ThinkPads; never had any significant issues before this. I know from experience that their technical support is stellar. I have two boxes arriving today to ship the systems in for repairs.

 

Good luck in your journey, fellow ThinkPadder.

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10 Posts

08-18-2017

AU

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  • Message 5 of 27

Re: T470 Heavy CPU Throttling on Battery

2017-08-31, 8:45 AM

There are now multiple threads on this issue:

 

Lenovo needs to state whether they're:

- treating this issue as a fault with the device and/or the BIOS and how they intend to resolve it (BIOS updates or recall)

- not treating this issue as a fault: in this case they're making misleading claims about the laptop's performance and battery life in their advertising

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4 Posts

08-26-2017

CA

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  • Message 6 of 27

Re: T470 Heavy CPU Throttling on Battery

2017-08-31, 9:11 AM

Because I was within the 30 days of my invoice, I ended up mailing the T470 back today, and Lenovo has said they will waive the 15% restocking fee. Instead I have ordered a T470s which, as far as I can tell, does not suffer from this issue. I was not willing to wait for Lenovo to fix an issue they haven't even acknowledged yet on a laptop that is only two weeks old.

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5 Posts

08-24-2017

IT

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  • Message 7 of 27

Re: T470 Heavy CPU Throttling on Battery

2017-09-01, 13:26 PM

Hi,

My machine is also affected by the issue.

I am trying to understand exactly what the problem is.

 

Can anybody confirm that the CPU throttling happens when the system switches between the use of the two batteries?

If this is the case, then maybe a BIOS update will be able to solve the issue.

My machine (T470, 20HD, BIOS 1.32) caps the CPU at 400 MHz when the system stops using the internal battery and starts using the external one.

In particular, if I boot the laptop when the internal battery is drained, then it starts using the external one right away and the throttling issue does not occur.

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6 Posts

09-13-2017

US

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  • Message 8 of 27

Re: T470 Heavy CPU Throttling on Battery

2017-09-13, 1:27 AM

I've been thinking along the same lines... it could be the event of a change that sends the signal...or it could be the battery itself that's sending an event (although my debug tracing so far doesn't point to an external event).

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14 Posts

09-20-2017

US

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  • Message 9 of 27

Re: T470 Heavy CPU Throttling on Battery

2017-09-20, 9:12 AM

Has anyone with this issue had a resolution? My t470 i7 is having a similar issue. When "battery 2" gets to 5%, my entire system throttles. It's currently on bios 1.39. 

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18 Posts

09-13-2017

CA

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  • Message 10 of 27

Re: T470 Heavy CPU Throttling on Battery

2017-09-20, 9:23 AM

There is some more activity over in this thread: https://forums.lenovo.com/t5/forums/v3_1/forumtopicpage/board-id/tp01_en/page/9/thread-id/117928

 

But I don't have a resolution yet. You're lucky tho, mine seems to throttle after 5-10 minutes on battery power. Both batteris at 90% or so!

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