DickieDebbil
2 Bronze

Dell M4800 CPU locked in low power state

I have a Dell M4800 with a Core i7 4900MQ, however I cannot get it to run above 800MHz - even on Prime95. I have tried enabling the high performance power plan but to no avail. CoreTemp is not reporting high temperatures so that is not the issue.

Also the GPU *may* be running at 405MHz when it should be at 666MHz, although I've had conflicting readouts from different programs on that. Again, no high temps.

Does anyone know what the problem might be here?

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17 Replies
8 Xenon

RE: Dell M4800 CPU locked in low power state

Does the system correctly identify the AC adapter, or does it show "unknown" in setup (F2 at powerup)?

If the AC adapter is not correctly identified (or is a non-Dell third party adapter), the system will run as if on battery all the time -- keeping the CPU speed exactly as you see it.

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DickieDebbil
2 Bronze

RE: Dell M4800 CPU locked in low power state

Thanks for your reply. In the 'battery information' section, it says 'AC Adapter = 130W'. It is the original Dell power supply.

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DickieDebbil
2 Bronze

RE: Dell M4800 CPU locked in low power state

Anyone got a solution for this?

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Moderator
Moderator

RE: Dell M4800 CPU locked in low power state

Hi Dickie,

What operating system is installed?  If you haven't already, I would suggest flashing the BIOS:

www.dell.com/.../driversdetails

I would then try disabling C-States and SpeedStep in the BIOS/setup. If it's still the same, what happens if you try a clean boot?

support.microsoft.com/.../how-to-perform-a-clean-boot-in-windows

Let us know how you get on.

Thanks


DELL-Alasdair R
Social Media Support
#IWork4Dell
I'm based in the UK and I'm usually available Monday to Friday 10am-5pm GMT (BST)
Get Support on Twitter @DellCaresPro


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DickieDebbil
2 Bronze

RE: Dell M4800 CPU locked in low power state

Thanks for the reply. It's running Windows 10. I have updated to the latest BIOS but that didn't fix it.

I tried disabling SpeedStep and C-States, and that unlocked more mutipliers, although it didn't seem to want to run above x29. I then tried just with SpeedStep disabled and it was running up to an x38 multiplier (the true maximum). In both cases, with Prime95 running, the CPU strangely dropped down to an x23 multiplier.

I don't really want to run it like this though as the drain on the battery will be much higher. What can I try to get it running with the full range of multipliers?

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Moderator
Moderator

RE: Dell M4800 CPU locked in low power state

Enable SpeedStep again, then boot to Windows and open MSCONFIG.

Select "boot" > "advanced options" then check the "number of processors" box and select the maximum number of CPUs.

Hopefully that should do it for you.


DELL-Alasdair R
Social Media Support
#IWork4Dell
I'm based in the UK and I'm usually available Monday to Friday 10am-5pm GMT (BST)
Get Support on Twitter @DellCaresPro


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DickieDebbil
2 Bronze

RE: Dell M4800 CPU locked in low power state

This solution partially worked but not entirely - now when it is running on battery it has access to higher multipliers, but as soon as I plug in the charger, it goes back down to 8x and will not budge from there.

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DickieDebbil
2 Bronze

RE: Dell M4800 CPU locked in low power state

Can anyone suggest a fix?

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8 Xenon

RE: Dell M4800 CPU locked in low power state

Given the last description, first try a new OEM Dell adapter -- 130W for integrated video or 240W for discrete.  If that doesn't solve the problem, replace the DC power jack.  If that doesn't solve it,  the issue is with the mainboard -- which is expensive to replace, but likely the only solution to the problem.

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