SOLUTION: CPU Throttling on Dell Latitude Ultrabooks (E7440, E7240) after power exceptions

Recently I have seen multiple instances (fairly rarely, but nevertheless) of the newer Dell Latitude Ultrabooks (circa 2013/2014 models, E7440 and E7240 specifically) throttling CPU frequencies under exceptional power conditions (such as possibly a misbehaving AC adapter or extremely low battery condition while under load).  I haven’t confirmed the exact circumstances which lead to this behavior, but I do know of a solution.

I first noticed this when a client recently reported sluggish operation of his brand-new E7440 Ultrabook… which, of course, made little sense considering the blazingly-fast parts (SSD included) that we purchased for him.  I checked the software briefly and saw no issues which would suggest configuration problems.  However, upon opening Task Manager, under the Performance tab, the CPU frequencies were reportedly below 400 MHz permanently–which, of course, is incredibly low considering the max Turbo Boost frequency of the i5 Haswell CPU he had of 2.8 GHz.  Fortunately, I had seen this problem once before.

My theory is that it is likely related to power disruption conditions, as I have only thus far seen it happen in circumstances where an AC adapter was not providing proper voltage or where the machine was in a very low battery state while sustaining heavy CPU loads for some reason (Windows Updates, etc.).  The machine responds by throttling CPU clock rates to protect itself from possible damage, but the problem is that it never reverts from this throttled state until it is powered off and the battery is removed.

Fortunately, the solution is easy, if not a bit difficult to discover.  All that is required is a BIOS update to the latest firmware available from Dell (support.dell.com, search for your particular model).  In my most recent client’s case, an upgrade from A05 to A15 immediately corrected the problem.  It remains to be seen whether it recurs, but I do not expect it to given the last instance I saw, where we did just the same thing and the problem was permanently corrected.

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11 thoughts on “SOLUTION: CPU Throttling on Dell Latitude Ultrabooks (E7440, E7240) after power exceptions

  1. Still after upgrading to BIOS A14 and later A15 the problem remains!
    The only solution is always to turn machine off or reboot.

  2. It does appear that exposure to extreme heat or direct sunlight for extended periods of time can provoke this permathrottle behavior even on the newest firmwares for the Latitude E7440. I wonder if Dell will be issuing another update to correct that problem, as it most certainly seems to be something which a firmware update could correct.

  3. same here – A18 and still has this problem (started 2 days ago)
    Restart doesn’t help

  4. Update:

    I think it is partially solved now:

    1. Before I posted this issue, I downgraded the bios (to 01) and upgraded one by one, as some users have recommended. It didn’t help.
    2. Like some other users have mentioned over other forums, pressing the chassis resulted in changed clocks. I had the same issue. I disassembled the laptop and pin pointed the area and found that specific screw was (part of) the problem, probably pressing the metal plate behind the keyboard on some electrical parts. I’ve placed some thermal pads there and now it does not happen. Obviously, there is some problem with the hardware or software in this case – not sure at all it’s the MB fault.

    Anyway, it seems like it repeats itself, so for anyone that reads this – you can ask if you want to know what exactly I did and where it was

  5. Hey e,

    how exactly did you do it? Which screw was the problem?

    looking forward to your answer

  6. Dear e,

    can you please describe what exactly you found / did?
    I do experience problems even with the newest BIOS (A20), among others similar to what Steve Schardein describes, only a lot more serious, that makes the notebook practically unusable in the summer.

    Anyone else ideas / solutions / experience?

  7. I had the exact same issue, and found the issue to be a loose power connector (in the back of the docking) to the docking station of my Dell Latitude E7470.

    Plugged it properly in, and the problem went away 😀

  8. I had the same issue with or without the dock. IT updated my laptop with the latest BIOS but it didn’t fix the issue.

    However, pressing the back of the laptop chassis did, in fact, make the laptop CPU goes up again, which was suggested in the previous post. Thanks

  9. The actual fix is to remove the battery, hold down the power for 5 seconds, reconnect the battery and tada — the laptop will not throttle down + lock to ridiculously low speeds anymore.

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